Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
METHOD OF MAKING A POROUS PREFORM IN SILICON CARBIDE WITH CONTROLLED POROSITY AND SILICON CARBIDE POROUS PREFORM
The present invention relates to a method of making a porous preform in silicon carbide with controlled porosity. The method comprises the operating steps: a) forming a mass of silicon carbide powdersin a mould obtaining a semi-finished preform with an initial porosity [Phi]1; b) pre-sintering said semi-finished preform in an inert atmosphere at a temperature in the range of 1,600 DEG C to 2,000DEG C, obtaining a pre-sintered preform with an intermediate porosity (2) higher than the initial porosity ([Phi]1); c) subjecting said pre-sintered preform to one or more heat treatment cycles, wherein each heat treatment cycle comprises in sequence: a sub-phase c1) of oxidation in air at a temperature in the range of 700 DEG C to 1, 250 DEG C; and a sub-phase c2) of partial sintering at a temperature in the range of 1,600 DEG C to 2,000 DEG C. After the aforesaid step c) a porous preform in at least partly sintered silicon carbide is obtained with a final porosity [Phi]3 higher than the intermediate porosity [Phi]2 of said sintered preform. Each heat treatment cycle causing a progressive increase of the porosity of said preform. The number of heat treatment cycles to be performed on saidpre-sintered preform is defined as a function of the value of final porosity [Phi]3 to be obtained in the porous preform of at least partially sintered silicon carbide so as to control the final porosity value [Phi]3 of the porous preform.
本发明涉及以碳化硅制作具有受控孔隙率的多孔预成型件的方法。该方法包括操作步骤：‑a)使许多碳化硅粉末在模具中成型，以获得具有初始孔隙率φ1的半制成预成型件；‑b)在惰性气氛中于1,600℃至2,000℃的范围中的温度处对所述半制成预成型件进行预烧结，以获得具有比初始孔隙率(φ1)高的中间孔隙率(φ2)的经预烧结的预成型件；‑c)使所述经预烧结的预成型件经受一个或多个热处理循环。每个热处理循环依次包括：‑在空气中于700℃至1,250℃范围中的温度处进行氧化的子阶段c1)；和‑在1,600℃至2,000℃的范围中的温度处进行部分烧结的子阶段c2)。在前述步骤c)之后，获得了具有最终孔隙率φ3的至少部分经烧结碳化硅的多孔预成型件，该最终孔隙率φ3比所述经烧结的预成型件的中间孔隙率φ2高。每个热处理循环使所述预成型件的孔隙率逐渐增大。根据待在至少部分经烧结碳化硅的多孔预成型件中获得的最终孔隙率φ3的值来限定待对所述经预烧结的预成型件执行的热处理循环的次数，以便控制多孔预成型件的最终孔隙率值φ3。
METHOD OF MAKING A POROUS PREFORM IN SILICON CARBIDE WITH CONTROLLED POROSITY AND SILICON CARBIDE POROUS PREFORM
The present invention relates to a method of making a porous preform in silicon carbide with controlled porosity. The method comprises the operating steps: a) forming a mass of silicon carbide powdersin a mould obtaining a semi-finished preform with an initial porosity [Phi]1; b) pre-sintering said semi-finished preform in an inert atmosphere at a temperature in the range of 1,600 DEG C to 2,000DEG C, obtaining a pre-sintered preform with an intermediate porosity (2) higher than the initial porosity ([Phi]1); c) subjecting said pre-sintered preform to one or more heat treatment cycles, wherein each heat treatment cycle comprises in sequence: a sub-phase c1) of oxidation in air at a temperature in the range of 700 DEG C to 1, 250 DEG C; and a sub-phase c2) of partial sintering at a temperature in the range of 1,600 DEG C to 2,000 DEG C. After the aforesaid step c) a porous preform in at least partly sintered silicon carbide is obtained with a final porosity [Phi]3 higher than the intermediate porosity [Phi]2 of said sintered preform. Each heat treatment cycle causing a progressive increase of the porosity of said preform. The number of heat treatment cycles to be performed on saidpre-sintered preform is defined as a function of the value of final porosity [Phi]3 to be obtained in the porous preform of at least partially sintered silicon carbide so as to control the final porosity value [Phi]3 of the porous preform.
本发明涉及以碳化硅制作具有受控孔隙率的多孔预成型件的方法。该方法包括操作步骤：‑a)使许多碳化硅粉末在模具中成型，以获得具有初始孔隙率φ1的半制成预成型件；‑b)在惰性气氛中于1,600℃至2,000℃的范围中的温度处对所述半制成预成型件进行预烧结，以获得具有比初始孔隙率(φ1)高的中间孔隙率(φ2)的经预烧结的预成型件；‑c)使所述经预烧结的预成型件经受一个或多个热处理循环。每个热处理循环依次包括：‑在空气中于700℃至1,250℃范围中的温度处进行氧化的子阶段c1)；和‑在1,600℃至2,000℃的范围中的温度处进行部分烧结的子阶段c2)。在前述步骤c)之后，获得了具有最终孔隙率φ3的至少部分经烧结碳化硅的多孔预成型件，该最终孔隙率φ3比所述经烧结的预成型件的中间孔隙率φ2高。每个热处理循环使所述预成型件的孔隙率逐渐增大。根据待在至少部分经烧结碳化硅的多孔预成型件中获得的最终孔隙率φ3的值来限定待对所述经预烧结的预成型件执行的热处理循环的次数，以便控制多孔预成型件的最终孔隙率值φ3。
METHOD OF MAKING A POROUS PREFORM IN SILICON CARBIDE WITH CONTROLLED POROSITY AND SILICON CARBIDE POROUS PREFORM
以碳化硅制作具有受控孔隙率的多孔预成型件的方法以及碳化硅多孔预成型件
ALEMANI MATTIA (Autor:in) / TIRONI MARIO (Autor:in) / MAGNANI GIUSEPPE (Autor:in) / BURGIO FEDERICA (Autor:in)
30.10.2020
Patent
Elektronische Ressource
Chinesisch
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