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日本政府正在资助一项对航空工业有重大影响的新型材料研究计划。这种材料的成份从样品的一边到另一边呈连续梯度变化。它们的一边可能是金属,另一边可能是陶瓷,中间则是金属和陶瓷的混合物。日本科学技术厅从1987年以来一直在研究这类“功能梯度”材料。现在它正在制定第二阶段的计划,其目的在于在三年之内耗资8亿日元(350万英镑)生产出可实用的材料。这项计划的目标之一就是开发一种一面是100%的陶瓷、另一面是100%的金属的材料。陶瓷面能抗极高温,金属面则提高其强度。它的目的是使宇宙飞船能抵卸它重返地球大气层时所产生的热,而不需要美国航天飞机目前所用的笨重的陶瓷贴砖。与瓷砖不同,这种功能梯度材料在它的成分之间没有接合点。而正是这一接合点可能在压力下破裂。
The Japanese government is funding a new material research program that has a major impact on the aviation industry. The composition of this material varies continuously from one side of the sample to the other. One side may be metal, the other may be ceramic, and the middle is a mixture of metal and ceramic. The Japan Science and Technology Agency has been studying such “functional gradient” materials since 1987. Now it is developing a second-phase plan that aims to produce 800 million yen (3.5 million pounds) worth of practical materials within three years. One of the goals of this plan is to develop a material that is 100% ceramic on one side and 100% metal on the other side. The ceramic surface can withstand extremely high temperatures, while the metal surface increases its strength. Its purpose is to enable the spacecraft to withstand the heat it generates when it re-enters the Earth’s atmosphere without the bulky ceramic tiles currently used by the US Space Shuttle. Unlike tiles, this functionally graded material has no joint between its components. And it is this junction that may break under pressure.