摘要:
The invention relates to subjecting boron carbide to a heat treatment at a temperature within a range of 1250.degree. C. to less than 1800.degree. C. prior to infiltration with a molten metal such as aluminum. This method allows control of kinetics of metal infiltration and chemical reactions, size of reaction products and connectivity of B.sub.4 C grains and results in cermets having desired mechanical properties.
摘要:
A braking component such as a brake pad, brake rotor, brake drum or clutch disk is comprised of a metal substrate having a friction material laminated on at least a portion of at least one face of the metal substrate, the friction material being a ceramic-metal composite comprised of a metal phase and a ceramic phase dispersed within each other, wherein the ceramic phase is present in an amount of at least about 20% by volume of the ceramic-metal composite. In particular, the braking component is a metal substrate, such as aluminum, having laminated thereto a ceramic-metal composite of a dense boron carbide-aluminum composite having high specific heat and low density.
摘要:
An improved ceramic honeycomb structure is comprised of at least two separate smaller ceramic honeycombs that have been adhered together by a cement layer comprised of a cement layer has at least two regions of differing porosity or cement layer where the ratio of toughness/Young's modulus is at least about 0.1 MPa·m1/2/GPa.
摘要:
A porous mullite composition is made by Forming a mixture of one or more precursor compounds having the elements present in mullite (e.g., clay, alumina, silica) and a property enhancing compound. The property enhancing compound is a compound having an element selected from the group consisting of Mg, Ca, Fe, Na, K, Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb, Lu, B, Y, Sc, La and combination thereof. The mixture is shaped and to form a porous green shape which is heated under an atmosphere having a fluorine containing gas to a temperature sufficient to form a mullite composition comprised substantially of acicular mullite grains that are essentially chemically bound.
摘要:
A hard drive disk substrate is formed of a multi-phase ceramic-based material having at least two phases with amorphous phases being present in an amount less than about 1 volume percent based on the volume of the ceramic-based material or at least one phase being free metal. A process for producing the ceramic-based disk substrate is produced by forming a flat disk of a porous ceramic and then infiltrating the porous ceramic with a metal whereby a multi-phase ceramic-based computer hard drive disk is produced. Additionally, a step of passivating the porous ceramic by elevating it to a temperature of about 1300.degree. to about 1800.degree. C. before the infiltrating step may be performed, such that the surfaces are passivated and the reaction kinetics can be controlled during the infiltrating step. A preferred composite material is made of a multi-phase boron carbide composite material including grains having peaks with an average roughness value, Ra, of between about 1 to about 200 .ANG., the roughness value being formed in situ by causing a micro hardness gradient of between about 19 and about 3200 Kg/mm.sup.2 in the various phases of the multi-phase boron carbide composite material.
摘要翻译:硬盘驱动器盘基板由具有至少两相的多相陶瓷基材料形成,其中无定形相以基于陶瓷基材料的体积或至少一相的量存在的量小于约1体积% 是免费金属。 通过形成多孔陶瓷的平板,然后用金属渗透多孔陶瓷来制造陶瓷基盘基板的方法,由此制造多相陶瓷基计算机硬盘驱动盘。 此外,可以在渗透步骤之前将其升高至约1300℃至约1800℃的温度来钝化多孔陶瓷的步骤,使得表面被钝化,并且可以在渗透步骤期间控制反应动力学 。 优选的复合材料由多相碳化硼复合材料制成,其包括具有平均粗糙度值Ra的峰值在约1至约200之间的晶粒,该粗糙度值通过使原位形成的微观硬度梯度 在多相碳化硼复合材料的各个相中约19至约3200Kg / mm 2。
摘要:
A braking component such as a brake pad, brake rotor, brake drum or clutch disk is comprised of a metal substrate having a friction material laminated on at least a portion of at least one face of the metal substrate, the friction material being a ceramic-metal composite comprised of a metal phase and a ceramic phase dispersed within each other, wherein the ceramic phase is present in an amount of at least about 20 percent by volume of the ceramic-metal composite. In particular, the braking component is a metal substrate, such as aluminum, having laminated thereto a ceramic-metal composite of a dense boron carbide-aluminum composite having high specific heat and low density.
摘要:
A brake component wherein at least a portion of said brake component is a ceramic metal composite (CMC), the CMC having an interconnected ceramic phase and a noncontiguous metal phase dispersed within the interconnected ceramic phase. In particular, a CMC of dense boron carbide-aluminum composite having high specific heat and low density is described.
摘要:
A porous mullite composition is made by forming a mixture of one or more precursor compounds having the elements present in mullite (e.g., clay, alumina, silica) and a property enhancing compound. The property enhancing compound is a compound having an element selected from the group consisting of Mg, Ca, Fe, Na, K, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, B, Y, Sc, La and combination thereof. The mixture is shaped and to form a porous green shape which is heated under an atmosphere having a fluorine containing gas to a temperature sufficient to form a mullite composition comprised substantially of acicular mullite grains that are essentially chemically bound.
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 hard drive disk substrate is formed of a multi-phase ceramic-based material having at least two phases with amorphous phases being present in an amount less than about 1 volume percent based on the volume of the ceramic-based material or at least one phase being free metal. A process for producing the ceramic-based disk substrate is produced by forming a flat disk of a porous ceramic and then infiltrating the porous ceramic with a metal whereby a multi-phase ceramic-based computer hard drive disk is produced. Additionally, a step of passivating the porous ceramic by elevating it to a temperature of about 1300.degree. to about 1800.degree. C. before the infiltrating step may be performed, such that the surfaces are passivated and the reaction kinetics can be controlled during the infiltrating step. A preferred composite material is made of a multi-phase boron carbide composite material including grains having peaks with an average roughness value, Ra, of between about 1 to about 200.ANG., the roughness value being formed in situ by causing a micro hardness gradient of between about 19 and about 3200 Kg/mm.sup.2 in the various phases of the multi-phase boron carbide composite material.
摘要翻译:硬盘驱动器盘基板由具有至少两相的多相陶瓷基材料形成,其中无定形相以基于陶瓷基材料的体积或至少一相的量存在的量小于约1体积% 是免费金属。 通过形成多孔陶瓷的平板,然后用金属渗透多孔陶瓷来制造陶瓷基盘基板的方法,由此制造多相陶瓷基计算机硬盘驱动盘。 此外,可以在渗透步骤之前将其升高至约1300℃至约1800℃的温度来钝化多孔陶瓷的步骤,使得表面被钝化,并且可以在渗透步骤期间控制反应动力学 。 优选的复合材料由多相碳化硼复合材料制成,其包括具有平均粗糙度值Ra的峰值在约1至约200之间的晶粒,该粗糙度值通过使原位形成的微观硬度梯度 在多相碳化硼复合材料的各个相中约19至约3200Kg / mm 2。