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Swelling behaviour of acrylonitrile-butadiene copolymer rubber vulcanizates immersed in a nonprotonic solvent was studied by real-time pulsed nuclear magnetic resonance (n.m.r.) measurements. The temporal change of the proton spin-spin relaxation time, T 2 , during the swelling process was obtained. The T 2 signal for the rubber vulcanizates was resolved into two exponentially decaying components (short T 2 and long T 2 ). The short T 2 component is assigned to the constrained regions in the rubber matrix, which may be mainly located around the crosslinks, and the long T 2 component to the regions lying outside the constraints. It was suggested that the decreased change of the fraction of the short T 2 component by swelling is closely connected with the enhanced molecular mobility of the network chains between the adjacent crosslinks through the diffusion of the solvent. The restricted swelling behaviour of the carbon black-filled rubber vulcanizates was interpreted mainly in terms of the constrained molecular motions of the network chains through the rubber-filler interactions and spatial effects of the filler particles. It becomes clear that the real-time pulsed n.m.r. measurements complement the results of the macroscopic swelling measurements for the rubber vulcanizates with more detailed information on the molecular interactions between the rubber and solvent molecules.

SiC ceramics, coated with a niobium metal film (Nb-SiC) with and without subsequent Ar + ion irradiation, were subjected to a pin-on-disk friction and wear test in an ambient atmosphere with a diamond pin for 40 h. The friction coefficient between the SiC disk and a diamond pin was about 0.1. Niobium film deposition decreased the friction coefficient to about 0.04 with a normal load of 9.8 N. The wear of SiC was also reduced to one-eighth by the niobium deposition. The Ar + -ion-irradiated Nb-SiC had very high wear resistance; effectively no wear was detected in the samples irradiated to doses over 5 × 10 15 ions cm −2 .

The effects of ion implantation on the mechanical properties are reviewed for alumina, silicon carbide and fully-stabilized zirconia. It is demonstrated that by ion implantation, (a) hardness of the near surface layer is varied over a wide range, depending on ion dose and implantation temperature, (b) significant increases in the flexural strength are observed, (c) the resistivity against the crack initiation and propagation associated with Vickers indentation is increased, (d) the resistivity against lateral and radial crackings associated with scratching by a loaded diamond stylus is increased, (e) a reduction in the friction coefficient from 0.6 to 0.15 is observed for polycrystalline silicon carbide in sliding contact with a steel. These results are discussed in terms of microstructural changes, surface compression stress and amorphized surface layer of an increased plasticity.

The adhesive strength of the Zr film on sapphire was found to be increased by N+ ion irradiation. The tensile strength of the adhesion became more than 75 MPa when the specimen was irradiated to the dose of 5 × 1016/cm2 and above. The Zr film deposition and the subsequent ion irradiation were also found to increase the resistivity against the surface crack occurrence by scratching with the loaded diamond stylus. The interface between the Zr metal and sapphire was examined by RBS and TEM, and the interdiffusion of elements at the interface by N+ ion irradiation were confirmed. The metal film on ceramic, united together by ion irradiation, or a metal-ceramic surface composite was proposed to be a new material.

Zr thin films (100 nm) were vacuum-deposited on SiC single crystals and silica glass, and these specimens were irradiated with 80 keV N+ ions to a dose of 1 × 1017/cm2 at about 100 K. RBS showed that an interdiffusion layer of about 7 nm thickness was formed around the interface between the Zr film and the SiC or the SiO2. XPS studies demonstrated that the N+ implantations generate chemical bonds like ZrSi, ZrC, and ZrOSi in the intermixed layer.

Effects of ion implantation and subsequent thermal annealing on the fracture stress of single-crystalline α-Al2O3 have been investigated for 400 keV N and 300 keV Ni ions. Upon N or Ni implantation, the flexural strength of a specimen 7 × 25 × 1 mm3 in size increased by 20 to 60% in the ion dose range from 1 × 1015 to 1 × 1017 ions cm 2 . By post-implantation thermal annealing, the relative flexural strength for the N implanted specimen recovered gradually with annealing temperature followed by a complete recovery at around 1300°C. This behavior of recovery for flexural strength has been found to be similar to that for radiation damage. On the other hand no recovery of flexural strength has been observed for the Ni implanted specimen, in which a spinel compound NiAl2O4 formed upon thermal annealing at temperatures above 1000°C. In N implantation, the strengthening results entirely from the effect of radiation damage, whereas in Ni implantation the formation of a surface NiAl2O4 layer with post-implantation thermal annealing is also effective in the strengthening.

SiC ceramics, with and without niobium metal film (Nb/SiC) and Ar + ion-irradiated Nb/SiC were subjected to a pin-on-disk friction-and-wear test with a diamond pin for 40 h. The metal film deposition reduced the friction coefficient and the wear, and no wear found in the irradiated Nb/SiC.