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The effects of adding iron oxide to ceramic glaze formulations were studied in this study. Iron oxide was added in different weight ratios into the reactive transparent glaze, reactive opaque glaze, and transparent glaze formulations. The iron oxide content in the glaze composition, the coloring mechanisms, the phase distributions, and surface properties at temperatures of 950–1000-1050-1200 °C in the oxidation firing medium were investigated. Scanning Electron Microscopy (SEM) to determine the microstructural and morphological characterizations of the test glazes, X-Ray Diffractometry (XRD) to determine the crystallographic properties and phases, and X-Ray Fluorescence (XRF) analyses to determine the elemental and chemical composition were performed. In addition to these, surface images were examined with Digital Microscope (DM) and Commission Internationale de l'Eclairage (CIE) L*a*b, and water absorption values were compared. In addition, taking into account environmental factors, a comparison of ceramic glazes with the same amount of waste iron oxide was also performed for same purpose. As a result of the studies, it was observed that the addition of iron oxide and/or waste iron oxide did not have a negative effect, and coloring effects on the glaze layer were observed at different rates and firing temperatures.

A new pyrophosphate(V) of the formula Co5Cr2(P2O7)4 was obtained in the system Co2P2O7–Cr4(P2O7)3 as a result of solid-state reactions taking place between different reactants. The new compound crystallizes in the orthorhombic system and belongs to the family of pyrophosphates of the general formula M52+M23+(P2O7)4 and is probably isostructural with Fe52+Fe23+(P2O7)4. Powder diffraction pattern, infrared spectrum and SEM image of the new compound were presented. As a new potential inorganic pigment, Co5Cr2(P2O7)4 was tested for its thermal stability, particle size distribution and colour properties, which were studied both for powder and after introduction into organic matrix and leadless ceramic glaze. The colour of Co5Cr2(P2O7)4 powder was defined as deep grey with the colour coordinates L*/a*/b* = 60.63/-1.42/-3.41 and according to the hue angle (h° = 247.39°) it belongs to the blue region. Co5Cr2(P2O7)4, with its relatively high thermal stability (t m = 1230 ± 10 °C) and appropriate colour properties, is a good candidate to be used as inorganic pigment for colouring of acrylic paints. In the case of leadless glaze, the obtained compound acts as a dye.

In this paper, high color performance vanadium ion (V4+) doped ZrSiO4 (V-ZrSiO4) blue pigment with low doping amount has been successfully synthesized by inorganic sol–gel route. According to the phase evolution and color behavior of the samples, the formation mechanism of the V-ZrSiO4 pigment was revealed. Besides, due to the immobilization effect of the gel network and the high precursor reactivity, the reported synthesis route has extremely high vanadium utilization ratio (99.69%). Based on the results of XPS and XRF analysis, it is found that the valence state of vanadium ion in the V-ZrSiO4 pigment is 4+, meanwhile, the vanadium cations are heterogeneously distributed in the pigment particles and are enriched within the outer layers. Compared with the previously reported V-ZrSiO4 pigments, the as-prepared V-ZrSiO4 pigment shows a bright blue hue (b*=–22.01), in which the theoretical content of V4+ is only 2 mol%. After applying on ceramic glaze, the V-ZrSiO4 pigment exhibited superior coloring performance and high-temperature stability, indicating its potential application in ceramic decoration. This work provides a facile strategy to synthesize high color performance ion-doping type pigment.

One of the factors determining the life of ceramic glazes used for decorative purposes is the glaze's re-sistance to abrasion and chemicals. The abrasion resistance of the glaze can be improved by increasing the hardness of the glaze. One of the ways to increase the hardness of the glaze is the creation of suitable glass-ceramic systems in which a harder crystalline phase or phases are developed from the glassy matrix. It has been determined that surface defects such as staining, and abrasion occur on the surfaces of the metallic glazed products produced after exposure to low-concentration chemicals. In the present study, it was aimed to develop recipe in an attempt to improve the resistance of the produced metallic surface products against surface defects. Chemical analysis of the used raw mate-rials was done by X-Ray fluorescence spectroscopy and their components were determined, and recipes were created in the light of chemical components. The characteristic melting behaviours of the created glaze recipe were determined by performing heat microscopy analysis. The behaviour of the recipes containing different amount of metal oxide powders (iron oxide, copper oxide, manganese oxide) from commercial companies on abrasion and metallic/artistic surface obtainment were investigated. It was determined that the acid/alkali resistance of the obtained metallic glaze recipes, as well as the results of resistance to citric acid, household chemicals, and swimming pool salts were improved. Also, matte glazes for wall tiles with metallic appearance, speck effect, and abrasion-resistant, and compatible with industrial fast-firing conditions have been developed., Dekoratif amaçlı olarak kullanılan, seramik sırların ömrünü belirleyen faktörlerin başında sırın aşınma ve kim-yasallara karşı direnci yer almaktadır. Sırın aşınma direnci, sır sertliğinin arttırılmasıyla iyileştirilebilmektedir. Sırın sertliğini arttırmanın yollarından biri; camsı matristen daha sert kristal faz ya da fazların geliştirildiği uygun cam seramik sistemlerin oluşturulmasıdır. Geliştirilen metalik sırlı ürünlerin düşük konsantrasyonlu kimyasallara maruz bırakılmasından sonra yüzeylerinde leke tutma ve aşınma gibi yüzey hatalarının meydana geldiği tespit edilmiştir. Bu çalışmada, üretilen metalik yüzeyli ürünlerin yüzey hatalarına karşı dayanımlarını arttırmak için reçeteler geliştiril-mesi amaçlanmıştır. Kullanılacak olan hammaddelerin kimyasal analizleri X-Ray flüoresans spektroskopisi ile analiz edilerek bileşenleri tespit edilmiş olup reçeteler bu bilgiler ışığında oluşturulmuştur. Oluşturulan sır reçetesinin karak-teristik ergime davranışları, ısı mikroskobu analizi yapılarak tespit edilmiştir. Ticari firmalardan alınan metal oksit tozlarının (demir oksit, bakır oksit, mangan oksit) farklı oranlarda kullanılmasıyla oluşturulan reçetelerin aşınmaya ve metalik/artistik yüzey elde etmek üzerine davranışları araştırılmıştır. Elde edilen metalik sır reçetelerin asit/alkali da-yanımlarını geliştiği ve buna ek olarak sitrik asit, ev kimyasalları ve yüzme havuzu tuzlarına dayanım sonuçlarının ise iyileştirildiği tespit edilmiştir. Aynı zamanda endüstriyel hızlı pişirim koşullarına uyumlu metalik görünümlü, benek efektli ve aşınmaya dirençli, duvar karosu mat sırlar da geliştirilmiştir.

In this article, rutile-perovskite multi-phase composite was produced using mechano-chemical method followed by calcination with metatitanic acid and GCC as raw materials. The relative parameters in mechano-chemical method, such as slurry concentration, grinding time and ball to powder ratio, and the relative parameters in calcination, namely calcination temperature and calcination time, were researched systematically in order to get the optimum value. The structure and morphology of the final product were characterized and the reaction mechanism was investigated. The final product, namely the rutile-perovskite multi-phase composite, has excellent pigment properties comparable to titanium white. It also has excellent performances in coatings and ceramic glaze. All of these prove that the produced rutile-perovskite multi-phase composite can be used extensively in industry due to its excellent pigment properties together with simple reaction conditions.

Aphysicochemical analysis was undertaken of fragments of medieval glazed ceramic found at different times in medieval towns located in the Chui, Talas, and Kochkor Valleys of Kyrgyzstan. The samples of glazed ceramic were studied by means of x-ray fluorescence and microscopic analyses. The physicochemical studies of the ceramic glaze from different archaeological complexes on the territory of Kyrgyzstan made it possible to identify the colorants and their features as well as the coloring technology and to note important moments in the historical development of the Gonchar crafts associated with the history of glazed ceramics in the countries of Central Asia.

In this study, the effect of seashell utilization as a replacement for calcite on the surface features and optical properties of white ceramic glazes was investigated. As received seashells collected from Black Sea beaches of Samsun, Turkey and purified seashells at 700°C for 1 h were used as calcite replacement by 15 wt.%. Seashell powders were incorporated to white glaze compositions which are applied on the surface of different fired clay bodies such as red clay, chamotte, white and porcelain by dipping technique. Next, the glazed green bodies were sintered at 1100ºC for 8 h. Following to TG-DTA, heating microscope, XRD and optical analysis, the obtained results exhibited that as received seashell powder (SP-1) was composed of calcite (CaCO3), whereas purified seashell powder (SP-2) comprised aragonite (CaCO3) and calcium oxide (CaO). The iron (hematite) content in red clay and the impurities in seashells composition caused specks and crawlings on the surface of glazed red clay bodies and of some glazes containing seashell, respectively. In generally, the higher CaO content in SP-2 enhanced gloss (60°) values, and whiteness values of most glazed surfaces were closed to each other. The color of chamotte bodies increased redness-greenness values. The variations in optical parameters were mainly associated with the difference in body compositions. SP-1 contained glaze, applied on porcelain body, was selected as optimal because that had 33 gloss value, high whiteness (87) and no surface defect. Therefore, the utilization of as received seashells by 15 wt.% as calcite replacement allows eco-friendly and cost-effective production of white ceramic glazes without any additional heat treatment.

The present study reports the impact of the introduction of nano-grained quartz (SA = 325 m2/g) into the composition on the structure and properties of the ceramic glaze of the CMAS-Na2O–K2O system. The results were compared to the glaze which had an identical oxide composition, with a difference that quartz was introduced in the form of quartz powder with a much smaller specific surface area SA = 1.41 m2/g. Both glazes are characterized by a large part of the glassy phase, above 90% by volume. The results obtained show a higher arrangement of the continuous glassy phase structure in the glaze with the addition of nano-quartz. This glaze also shows significantly higher values for all measured mechanical properties. It seems that if, in the near future, new cheaper methods for the production of nano-quartz are developed, it will be a new interesting direction of research aimed at improving the parameters of glazes and glass-ceramic materials of CMAS type.

This topic is based on the research and development of inorganic silver-loaded antibacterial materials with good antibacterial activity, and the preparation of silver-loaded calcium carbonate inorganic nano-antibacterial agents by redox reaction. At the same time, the mixed rare earth oxide was added to the ceramic glaze containing silver nano antibacterial agent, and the nano antibacterial building sanitary ceramics were prepared by firing at 1180 °C in an oxidizing atmosphere. This experiment investigated the effect of adding mixed rare earth oxides on the quality and properties of glaze. Experiments show that the new glaze has stronger antibacterial effect than the nano antibacterial glaze without mixed rare earth oxide, and the glaze quality is good. After adding 0.5 wt% of mixed rare earth oxide, the whiteness, abrasion resistance, hardness and thermal shock resistance of the glaze were significantly improved.This topic is based on the research and development of inorganic silver-loaded antibacterial materials with good antibacterial activity, and the preparation of silver-loaded calcium carbonate inorganic nano-antibacterial agents by redox reaction. At the same time, the mixed rare earth oxide was added to the ceramic glaze containing silver nano antibacterial agent, and the nano antibacterial building sanitary ceramics were prepared by firing at 1180 °C in an oxidizing atmosphere. This experiment investigated the effect of adding mixed rare earth oxides on the quality and properties of glaze. Experiments show that the new glaze has stronger antibacterial effect than the nano antibacterial glaze without mixed rare earth oxide, and the glaze quality is good. After adding 0.5 wt% of mixed rare earth oxide, the whiteness, abrasion resistance, hardness and thermal shock resistance of the glaze were significantly improved.

A frit is a glassy ceramic composition that has been fused, quenched, and granulated. A single frit or a mixture of frits and ceramic materials forms a ceramic glaze. The purpose of this pre-fusion is to render any soluble and/or toxic components insoluble by rendering it inert in a glassy composition with silica and other added oxides. The ceramic glaze dispersed in water (ceramic slip) is deposited on a ceramic body and fired for waterproofing and aesthetic purposes. Multicomponent frits (zinc-potassium borosilicate system) with similar behavior to conventional ceramic frits for single-firing ceramic glazes (“monoporosa” glazes fired at 1080 °C) were prepared by Sol-Gel methods (monophasic and polyphasic gels) avoiding the pre-fusion and characterized as photocatalytic agents (showing high degradation activity on Orange II). The effect of doping with bandgap modifiers (V2O5, Sb2O5 and SnO2) and also with devitrification agents (ZrO2 to crystallize zircon, Al2O3 to anorthite, Mo2O3 to powellite and ZnO to gahnite ZnAl2O4) were analyzed.

The increasing threat of multidrug-resistant microorganisms is a cause of worldwide concern. This motivates a necessity to discover new antimicrobial agents or new mechanisms for microorganism eradication, different from those currently used. Here, we report an effective antibacterial ceramic glaze that combines different bactericidal mechanisms. Specifically, the used methodology of the glaze results in glass-free edge crystallizations of feldspar structures at the ceramic surface. A combination of Rutherford backscattering spectroscopy, scanning electron microscopy, and Raman microscopy is used to determine the chemical elements and crystallizations at the ceramic surface. Moreover, Kelvin probe force microscopy demonstrates that the presence of glass-free edges in feldspar needle crystals (semiconductor phase) on a glass matrix (insulator phase) promotes the formation of semiconductor-insulator interface barriers. These barriers act as reservoirs of electric charges of ∼1.5 V, producing a discharge exceeding the microorganism membrane breakdown value (up to 0.5 V). Furthermore, the surface crystallizations account for the formation of a microroughness that limits biofilm formation. Both factors result in high antibacterial activity in the range of R > 4 for Escherichia coli and Staphylococcus aureus. This approach opens new possibilities to attain bactericidal surfaces and to understand the role of physical interaction as a main antimicrobial mechanism., The authors acknowledege the financial support by the projects MAT2017-86450-C4-1-R and MAT2017-86450-C4-3-R.

In this work, a polycarboxylate comb-like polymer was used as grinding aid for ceramic slurry, and the effect of addition of this grinding aid on ceramic process property was highlighted. The grinding efficiency of the polycarboxylate grinding aid (PG) in terms of the particle size distribution and specific surface of unit volume of the ceramic slurry being ground were investigated. Consequently, the PG that was synthesized via free radical polymerization under the condition of an APEG/AA/MA molar ratio of 0.3:1:1, an initiator dosage of 5 wt%, and a reaction time of 6 h at 90 °C, provided better grinding efficiency than those of the triethanolamine and other commercial grinding aids. Specifically, with a dosage of 0.21% and 2 h of grinding, the d97 and d50 of ceramic slurry decreased from 13.956 μm and 2.043 µm to 3.739 µm and 0.561 µm, respectively. The cumulative distribution, frequency distribution and SEM results exhibited a uniform particle size distribution for ceramic ground with PG-C. Furthermore, the sintering experiment indicated that a lower processing temperature was capable of producing ultrafine ceramic. These improvements indicated the potential application of the PG as an efficiency ceramic grinding aid, which further facilitating the preparation of uniform ultrafine slurry by a sand mill.

Perovskite pigments with SrCrxSn1−xO3−δ (x = 0.025, 0.05, 0.1, 0.2, 0.3) composition were prepared by a solid-state reaction, suspension mixing of materials and mechanochemical activation of initial reagents with calcination at high temperature. Results of thermal analysis show the effectivity of mechanochemical activation of reaction mixture that shifts the reaction course to lower temperature. Solid solution of SrSn0.975Cr0.025O3−δ was prepared at temperature 1200 °C. The optimal composition for synthesis of the intense red–pink powder is SrSn0.975Cr0.025O3−δ (L*/a*/b* = 36.34/14.21./1.12). Red–pink colour of the pigments is explained in terms of crystal field theory. The partial substitution of tin ions by chromium ions leads to the formation of the optical absorption bands corresponding to the O2p–Cr3d charge transfer transitions. Pigment is distinguished by good chemical stability in a molten ceramic glaze and high value of solar reflectance in the near-infrared region of light (R* ≈ 61%).

The zircon-based encapsulation carbon black (C@ZrSiO4) inorganic pigments with controllable size were successfully prepared by non-aqueous sol-gel method with the assistance of soft mechano-chemistry (SMC) activation precursors. The XRD and FT-IR results showed that the SMC activation enhanced the reactivity of precursors and facilitated the formation of ZrSiO4 phase with the calcination temperature at 900–1050 °C, indicating the successfully synthesis of pure ZrSiO4 phase. The average size of C@ZrSiO4 inorganic pigments significantly declined from 45.20 to 4.50 μm with the increase of SMC activation time of precursors, however, the L* values of pigments increased from 24.11 to 46.35. It was mainly because of the decreased amounts of protected carbon in ZrSiO4 matrix and the enhanced light reflectance, which lead to the slight color change from deep black to gray black tone. The colored glaze samples presented a black hue after applied in the ceramic glaze at 1200 °C. Moreover, the black hue intensity of glazed samples was higher than that of the corresponding C@ZrSiO4 inorganic pigments, indicating the prepared pigments have excellent tinctorial strength and hiding power. These results ensure that the obtained C@ZrSiO4 inorganic pigments possess the outstanding chromatic performance, excellent high-temperature stability, high chemical stability and suitable particle size, and exhibit great potential in the application of the industrial ceramic decoration.

The lime alkaline glaze, originated as early as 1300A.D, is typical of Chinese ancient transparent ceramic glaze in the dynasties of Yuan, Ming, and Qing. Imitation transparent glaze with the composition identical to that of the ancient glaze in the Ming and Qing dynasties was prepared at five different firing temperatures. FTIR spectra of the imitation glaze were analyzed by means of mathematical self-deconvolution, and the assignment of each component band was identified, showing that the glaze, with the increase of firing temperature, presented a higher level of polymerization degree in its network. Imitation glazes were artificially aged through water corrosion and annealing. FTIR decomposition spectra of aged glazes indicate that some silicon-bridging oxygen- silicon bonds were hydrolyzed during water corrosion, and that silicon-non-bridging oxygen-alkali bonds increased during low-temperature anneal. Finally, the FTIR results obtained from the artificial aged glazes were compared with those of the ancient glaze of the Ming and Qing dynasties, and aging condition of ancient glazes were inferred.

Gold and silver salt mixtures are incorporated in ceramic glazes for in situ development of mixtures of gold and silver nanoparticles (NPs) that subsequently allow for a wide spectrum of low metal loading color control within ceramic materials. Prior work has shown that gold NPs can be used to create vibrant, color-rich red pigments in high-temperature ceramic and glass applications, though the achievable diameter of the gold NP ultimately limits the available range of color. The current study significantly expands color control from traditional gold nanoparticle red through silver nanoparticle green via the alteration of gold-to-silver salt ratios incorporated in the glaze formulations prior to sintering. Nanoparticle-based coloring systems are tested in both oxidative and reductive firing atmospheres. While the oxidation environment is found to be prohibitive for silver NP stability, the reductive atmosphere is able to form and sustain mixtures of gold and silver NPs across a wide color spectrum. All glazes are analyzed via reflectance spectrometry for color performance and samples are characterized via TEM and EDS for composition and sizing trends. This study creates new groundwork for a color-controlled NP system based on noble metal ratio blends that are both nontoxic and achieved with radically lower metal pigment loading than traditional glazes.

In this study, silver nanoparticles (Ag NPs) were successfully synthesized by using the green chemistry method, which is simple, environment friendly, and economical by using plant extract obtained from Abelmoschus esculentus. The synthesized Ag NPs were characterized using ultraviolet–visible (UV–Vis) spectroscopy, thermogravimetric analysis, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray crystallography and X-ray photoelectron spectroscopy. The synthesized Ag NPs showed absorbance peaks at 432 nm in the UV–Vis spectroscopy. The mean particle size of Ag NPs was found to be 8.96 nm. The antimicrobial activity of Ag NPs was examined on Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Bacillus subtilis (B. subtilis) and Methicillin-resistant Staphylococcus aureus. Besides, the antibacterial activity of Ag NPs was compared with commercially available antibiotics (Penicillin–streptomycin and Ampicillin–sulbactam). Ag NPs exhibited excellent antimicrobial activity against gram-positive and gram-negative bacteria. In addition, Ag NPs were used in ceramic glaze, and thus, an antibacterial ceramic glaze was developed. © 2020, Islamic Azad University (IAU).

Metal borate nanoparticles Silver (Ag), copper (Cu) and Zinc (Zn) were produced for a novel boron containing antibacterial ceramic applications. Different concentration, temperature, time parameters were varied for obtaining hierarchical metal borate embedded formulations. Synthesized nanostructures showed interesting crystalline and optical properties since temperature and concentration adjustments provided correlated shape and surface properties. Chemical analysis and crystallinity of both copper and silver formulations were defined using XRD and confirmed that temperature plays a deep role on the production of nanostructures. XPS analysis together with TEM investigations comprehensively provided all atomic compositions with their corresponding energy values in survey and high resolution region. Morphology and atomic purity was analyzed using EDX and SEM measurements revealed the morphological orientation of the nanostructures without other impurities. FT-IR and UV-Vis spectroscopy provided optical information about the obtained metal borate nanoparticles. Finally metal borate nanoparticles were utilized for 1x1 cm ceramic glazing samples for antibacterial applications. Silver borate nanoparticles were found to be more active in low concentrations than copper and zinc borate structures after the antibacterial test results were unveiled against to gram positive and gram negative microorganisms.

To evaluate and compare color stability and gloss retention of ceramic stains and glaze under simulated toothbrushing using dentifrices with different relative dentin abrasion (RDA).Feldspathic porcelain, lithium disilicate, 3 mol% yttria partially stabilized zirconia, and 5 mol% yttria partially stabilized zirconia were evaluated. Ceramics were externally stained, glazed and mounted in the toothbrush simulator. A toothbrush with 300 g force was applied. Regular toothpaste (72 RDA) and charcoal toothpaste (RDA200) were used. Linear brushing motion with cycle intervals: 5 k, 10 k, 30 k, and 50 k was achieved. Change in color (CIEΔE2000) and gloss measurements were collected using a reflection spectrophotometer (Ci 7600, X-rite) at baseline and cycle intervals. Repeated measures analysis of variance within specimen factors (ceramic type, toothpaste and cycles) was performed.ΔEGlass-phase ceramics retain stains longer than zirconia ceramics. Charcoal toothpaste affect color and gloss stability. Ceramic glaze maybe lost within the first 6 months in patients' mouth.Long-term color and gloss stability of externally stained and glazed ceramics maybe a clinical concern. Charcoal toothpastes enhance loss of color and gloss of ceramic restorations.

A zircon encapsulated carbon black (C@ZrSiO 4 ) pigment with high color rendering was synthesized via facile non-aqueous acetic acid (NAA) assisted sol-gel method using carbon-containing precursors (zirconium n -propoxide and tetraethoxysilane) as in-situ carbon sources. The effects of the NAA amount and heat treatment temperature on the structure and properties of the synthesized encapsulation pigments were characterized by XRD, FT-IR, FE-SEM, HR-TEM, EDS, XPS and CIELAB colorimeter, respectively. The results showed that the C@ZrSiO 4 encapsulated pigments heating at 1000 °C for 2 h in N 2 atmosphere presented a dense and stable encapsulation structure as well as deep dark hue when the mole ratio of NAA and Zr (NAA/Zr) was 3:1, and the chromaticity values were L* = 21.20, a* = 0.56, b* = −0.09 and C ab = 0.57, respectively, which were contributed to the high homogeneity at atomic level in ZrSiO 4 sol and the tight bonding between carbon black carbonized by carbon containing group and zircon matrix. In addition, the pigment exhibited excellent chemical stability, thermal stability and tinctorial strength when it was used in water, acid, alkali, organic solvents and ceramic glaze. Especially, these pigments improved the utilization of raw materials and avoided the use of heavy metals or transition metals as coloring agent, which was an environment-friendly black ceramic pigment.

This study demonstrates the formation of nanoparticles (NPs) from metal salts within ceramic glazes, such that the use of this colorant technology is more accessible to artisans, employs less metal content, is less environmentally harmful, and allows for the use of traditional kilns. Gold NPs have been demonstrated to possess a specific, low material loading use as a ceramic glaze colorant via plasmon resonance. Pre-synthesized gold NPs that are added to ceramic glazes have been found to significantly change in size after firing in both reductive and oxidative atmospheres, but still maintain some size relationships and color properties. Unfortunately, it is not viable for the art community to fabricate and employ gold NP systems with high precision in a studio setting; however, the use of noble metal salts or metal oxides are realistic. To that end, this work investigates spontaneous gold and silver NP synthesis by the firing-induced development of NPs from metallic salts included within the glaze materials. Glaze samples with gold and silver salts are fired in reductive and oxidative environments, yielding a range of surface plasmon coloring effects for ceramic coloring. Additionally, the use of gold NP waste (precipitated Au NPs waste) was added to wet ceramic glazes to investigate firing effects on NPs precipitate and potential use as an alternative colorant. Sintering-induced NP nucleation and growth was observed after firing in both oxidation and reduction environments, although to differing degrees. The direct noble metal salt application process eliminates the need for preliminary gold NP synthesis, thus allowing for more practical and environmentally friendly methods in creating plasmonic resonance ceramic coloring, potentially reflective of the processes employed in ancient nanoparticle glasses.

Most traditional ceramic glazes employ high amounts of transition metal colorants that are toxic to the environment and can cause health issues in humans through surface leaching. Gold nanoparticles (Au-NPs) have been found to be environmentally friendly and non-toxic alternative metal colorant in ceramic glazes. The plasmon band observed with Au-NPs can result in vibrant solutions by manipulating NP size, shape, and concentration; however, the effects of traditional firing in both reductive and oxidative kilns on Au-NPs are poorly understood. Aside from ancient art processes whose mechanisms have not been fully explored, the use of Au-NPs as suspended ceramic glaze colorants remains somewhat unexplored. Au-NPs have been previously reported to diminish in size during sintering and possess significant differences in concentration with respect to reduction and oxidation firing atmospheres. As a means of studying possible degradation/renucleation processes within the glaze during firing, a systematic study introducing different diameter Au-NPs into the glaze materials was conducted with transmission electron microscopy and reflectance spectroscopy used to probe possible mechanisms which showed changes to Au-NP diameter and color intensity, making this work applicable to industry and art current practices.