A review of the influence of environmental humidity and water on friction, lubrication and wear

In the early 1970s in Japan, the United States and France it was found that additions of nitrogen into aluminum oxide resulted in new spinel-like phases. At about the same time there was much increased interest in oxynitrides, stimulated by Professor K. Jack in the UK and Y. Oyama in Japan. Following these activities a major research program in this area was initiated at the Army Materials and Mechanics Research Center in Watertown, Massachusetts in 1974. These efforts resulted in the first complete Al2O3–AlN phase equilibrium diagram and a process to reactively sinter to nearly full density, translucent aluminum oxynitride spinel ceramic, which was named AlON. Subsequently, the Raytheon Company further developed AlON into a highly transparent material (ALON™) with many applications including transparent armor and EM domes and windows, among others—the technology was recently transferred to the Surmet Corporation. This paper will review the early history, phase equilibrium, crystal chemistry, and properties of this material, along with more recent work in our laboratory on transient liquid phase sintering and new data on lattice parameter measurements. In addition, recent results of collaborative work on AlON's dynamic mechanical properties using plate impact, Kolsky bar and edge-on impact (EoI) experimental techniques, including preliminary modeling at the microstructural scale of AlON in the EoI test, will be presented.

AlON: A brief history of its emergence and evolution

Material-specific wear mechanisms : relevance to wear modelling

Effect of microstructure on the wear transition of zirconia-toughened alumina

The preparation of dense homogeneous zirconia-toughened alumina (ZTA) with high dry-sliding wear resistance is described These ZTA ceramics are obtained by sintering green compacts, made by colloidal filtration of well-defined ZrO2-Al2O3 particle suspensions, for 2 h at 1400°C The optimum solid and stabilizer concentrations for the filtration process were determined The sintered ZTA microstructure consists of a homogeneous distribution of zirconia grains in an alumina matrix with grain sizes of 02 and 05 µm, respectively In pin-on-disk tribological measurements at relatively high initial contact pressures (1130 MPa) and sliding speeds (05 m/s) a very low specific wear rate (about 5 × 10-8 mm3/(N·m)) and a coefficient of friction of 045–055 were found It is shown that, in this case, wear is dominated by abrasion and polishing

Processing of Homogeneous Zirconia-Toughened Alumina Ceramics with High Dry-Sliding Wear Resistance

Mechanical behavior of Al2O3-based ceramics can be improved by dispersion of pure or partially stabilized ZrO2 particles. The effective toughening or strengthening effect, which is operating in these composite materials, is determined by microstructural characteristics (composition, processing conditions) and environmental conditions (temperature, loading rate,…). The objective of this work has been to make a correlation between mechanical properties and wear resistance of alumina-zirconia composites. Wear tests were conducted employing a bloc-on-ring tribometer which consists of a steel ring rotating against plane ceramic specimens. Different environmental conditions were investigated: ambient air, and water. The wear volume is determined as a function of sliding distance. The dispersion of ZrO2 particles in Al2O3 matrix improves the fracture behavior but reduces the wear resistance. However, the addition of ZrO2 limits the water corrosion effect observed in Al2O3 materials. Wear seems to be controlled b...

Relationship between mechanical properties and wear resistance of alumina-zirconia ceramic composites

Etude des proprietes mecaniques de composites ceramiques Al 2 O 3 −AlON obtenus par frittage reactif a partir d'un melange Al 2 O 3 −AlN

F. Thevenot

Papers

Relationship between mechanical properties and wear resistance of alumina-zirconia ceramic composites

Reaction-sintering of an Al2O3-AION composite determination of mechanical properties

Preparation and microstructure of zirconia toughened alumina ceramics.