摘要:
Densified composites of a metal such as copper or aluminum with a titanium-silicon-carbide or titanium-aluminum-carbide ceramic material are prepared by forming the ceramic material into a body, and infiltrating the body with the molten metal. The metal is able to rapidly penetrate into void spaces, between grain boundaries and even into the crystal structure of the ceramic grains to form a composite. The starting ceramic material may be previously densified, in which case various types of gradient structures can be produced easily. The process can be operated at low pressures, and so the hot pressing methods that normally must be used to densify these ceramic materials can be avoided.
摘要:
A method of forming a porous mullite composition of acicular mullite grains having improved properties is described, where the mullite is formed at some time in the presence of a fluorine containing gas. For example, it has been discovered that improved properties may result from heating the mullite to a high temperature in an atmosphere selected from the group consisting of water vapor, oxygen, an inert gas or mixtures thereof or forming the mullite composition from precursors having an Al/Si ratio of at most 2.95.
摘要:
A method of forming a porous mullite composition of acicular mullite grains having improved properties is described, where the mullite is formed at some time in the presence of a fluorine containing gas. For example, it has been discovered that improved properties may result from heating the mullite to a high temperature in an atmosphere selected from the group consisting of water vapor, oxygen, an inert gas or mixtures thereof or forming the mullite composition from precursors having an Al/Si ratio of at most 2.95.
摘要:
A method of forming a porous mullite composition of acicular mullite grains having improved properties is described, where the mullite is formed at some time in the presence of a fluorine containing gas. For example, it has been discovered that improved properties may result from heating the mullite to a high temperature in an atmosphere selected from the group consisting of water vapor, oxygen, an inert gas or mixtures thereof or forming the mullite composition from precursors having an AL/Si ratio of at most 2.95.
摘要:
Densified composites of a metal such as copper or aluminum with a titanium-silicon-carbide or titanium-aluminum-carbide ceramic material are prepared by forming the ceramic material into a body, and infiltrating the body with the molten metal. The metal is able to rapidly penetrate into void spaces, between grain boundaries and even into the crystal structure of the ceramic grains to form a composite. The starting ceramic material may be previously densified, in which case various types of gradient structures can be produced easily. The process can be operated at low pressures, and so the hot pressing methods that normally must be used to densify these ceramic materials can be avoided.