%0 Journal Article
%T New Technology for Increasing Through-Life Reliability of Ceramics Components Using Self-Crack-Healing Ability
%A Kotoji Ando
%A Koji Takahashi
%A Wataru Nakao
%A Toshio Osada
%A Kae Iwanaka
%J Journal of Powder Technology
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/937312
%X Structural ceramics are superior to metallic materials in terms of their high-temperature strengths and critical heat proof temperatures. However, compared to metallic materials, ceramics exhibit lower fracture toughness, so they are more sensitive to flaws such as pores and cracks. The shortness considerably decreases the component reliability. To overcome the shortness, in this study, special attention is paid to structural ceramics with self-crack-healing ability. There are several advantages for using a material with self-crack-healing ability. (1) After an efficient machine operation, the materials are able to self-heal the cracks introduced by the machining. (2) The materials are able to self-heal the cracks introduced during service and recover the strength completely at healing temperature. However, ways of organizing the available knowledge to increase the through-life reliability of ceramics components have not been extensively studied. The authors propose a new concept and the corresponding flowchart. This new concept is a promising technique for increasing the through-life reliability of ceramics components with excellent self-crack-healing ability. 1. Introduction Structural ceramics are superior to metallic materials in terms of their high-temperature strengths and critical heat-proof temperatures. Structural ceramics are leading candidate materials for high-temperature applications such as components of gas turbines. However, compared to metallic materials, ceramics exhibit lower fracture toughness, so they are more sensitive to flaws such as pores and cracks. The reliability of structural ceramics in machinery is therefore limited by the following three problems. (1) Cracks occur during machining (e.g., grinding and polishing), considerably decreasing the component reliability. In order to prevent this, precise polishing is required in the final stage, which is time-consuming and lowers the fabrication efficiency and raises the fabrication cost. (2) In particular, cracks of depth about 10¨C30£¿¦Ìm affect the reliability. Nondestructive inspection technologies for detecting cracks of depth 10¨C30£¿¦Ìm have yet to be developed. (3) Cracks may occur for various reasons in components during their use at high temperatures. To overcome the above problems, in this study, special attention is paid to structural ceramics with self-crack-healing ability. There are several advantages to using a material that can heal its own surface cracks. First of all, if the self-healing of the surface crack is carried out after an efficient machine operation is
%U http://www.hindawi.com/journals/jpt/2013/937312/