铸造难熔金属复合材料用稀土陶瓷型芯结构及相关工艺
Rare earth-based core constructions for casting refractory metal composites, and related processes
铸造难熔金属复合材料用稀土型芯结构及相关工艺
A method of fabricating a core for a ceramic shell mold is disclosed. A porous core body is formed from at least about 50% by weight of at least one rare earth metal oxide. The core body is heated under heating conditions sufficient to provide the core with a density of about 35% to about 80% of its theoretical density. The core body is then infiltrated with a liquid colloid or solution of at least one metal oxide compound, e.g., rare earth metal oxides; silica, aluminum oxide, transition metal oxides, and combinations thereof. The infiltrated core body is then heated to sinter the particles without substantially changing the dimensions of the core body. Mold-core assemblies which include such a core body are also described. A description of processes for casting a turbine component, using the core, is also set forth herein.
本发明公开了一种陶瓷壳模具芯的制造方法。多孔芯体由至少一种稀土金属氧化物的重量的至少50%形成。堆芯体在加热条件下被加热，足以使堆芯密度达到其理论密度的35%到80%左右。然后用至少一种金属氧化物化合物（例如，稀土金属氧化物；二氧化硅、氧化铝、过渡金属氧化物及其组合）的液体胶体或溶液浸渍芯体。然后将浸渍的芯体加热以烧结颗粒，而不会实质性地改变芯体的尺寸。还描述了包括这种芯体的模芯组件。本文还阐述了使用芯模铸造涡轮部件的工艺描述。 Primary Examiner: KERNS, KEVIN P
Attorney, Agent or Firm:
GENERAL ELECTRIC COMPANY (GLOBAL RESEARCH 1 RESEARCH CIRCLE K1 - 3A59, Niskayuna, NY, 12309, US) Claims:
The invention claimed is:
1. A method of fabricating a core for a mold, comprising the following
steps: (a) forming a porous core body according to selected dimensions from a composition comprising a binder and at least about 50% by weight of at least one rare earth metal oxide, based on the total weight of the core body; (b) heating the core body under heating conditions sufficient to remove a substantial portion of the binder and provide the core with a density of about 35% to about 80% of its theoretical density; (c) infiltrating the core body with a liquid colloid or solution which comprises particles of at least one metal oxide compound or precursor thereof, selected from the group consisting of rare earth metal oxides; silica, alumina, transition metal oxides, and combinations thereof; and then (d) heat-treating the particle-infiltrated core body under heating conditions sufficient to sinter the particles without substantially changing the dimensions of the core body. 一种为模具制造芯的方法，包括以下步骤：（A）根据从包含粘合剂和至少一种稀土金属氧化物重量的50%（以重量计）的混合物中选择的尺寸形成多孔芯体；（b） 在加热条件下加热芯体，该加热条件足以除去大部分粘合剂，并使芯体的密度约为其理论密度的35%至80%；（c）用液体胶体或溶液渗透芯体，该液体胶体或溶液包含至少一种金属氧化物化合物或其前体的颗粒，选自稀土金属氧化物、二氧化硅、氧化铝、过渡金属氧化物及其组合；然后（d）在加热条件下对渗入颗粒的芯体进行热处理，该加热条件足以在不显著改变芯体尺寸的情况下烧结颗粒。
2. The method of claim 1, wherein the rare earth metal oxide of step (a) is selected from the group consisting of yttrium oxide, cerium oxide, erbium oxide, dysprosium oxide, ytterbium oxide, and combinations thereof.
根据权利要求1所述的方法，其中步骤（a）的稀土金属氧化物选自氧化钇、氧化铈、氧化铒、氧化镝、氧化镱及其组合。
3. The method of claim 1, wherein the composition of step (a) comprises at least about 65% of at least one rare earth metal oxide. 如请求项1之方法，其中步骤（a）之组成包含至少一种稀土金属氧化物之至少约65%。
4. The method of claim 1, wherein the rare earth metal oxide comprises yttria.
如请求项1之方法，其中所述稀土金属氧化物包含钇。
5. The method of claim 1, wherein the porous core body of component (a) is formed by a molding process.
根据权利要求1所述的方法，其中所述组件（a）的多孔芯体由成型工艺形成。
6. The method of claim 1, wherein the porous core body of component (a) is formed by a process selected from the group consisting of injection molding, transfer molding, compression molding, die pressing, investment casting, coagulation casting, gel casting, slip casting, extrusion, and combinations thereof.
根据权利要求1所述的方法，其中所述组件（a）的多孔芯体由从以下组中选择的过程形成：注射成型、转移成型、压缩成型、模压成型、熔模铸造、凝固铸造、凝胶铸造、滑动铸造、挤压及其组合。
7. The method of claim 1, wherein the core body is heated in step (b) under heating conditions sufficient to provide the core with a density of about 50% to about 75% of its theoretical density.
根据权利要求1所述的方法，其中，在步骤（b）中，在足以使芯具有约50%至约75%的理论密度的加热条件下加热芯体。
8. The method of claim 1, wherein the heat-treatment temperature of step (b) is in the range of about 900° C. to about 1800° C. 如请求项1之方法，其中步骤（b）之热处理温度在约900℃至约1800℃范围内。
9. The method of claim 1, wherein the heat treatment of step (b) is carried out in a furnace.
如请求项1之方法，其中步骤（b）之热处理系在熔炉中进行。 10. The method of claim 1, wherein the binder comprises at least one material selected from the group consisting of organometallic liquids; wax-based compositions; thermosetting resins, and combinations thereof.
如请求项1之方法，其中该黏合剂包含选自有机金属液体、蜡基成分、
热固性树脂及其组合之群之至少一种材料。
11. The method of claim 1, wherein the rare earth metal oxides of step (c) are selected from the group consisting of yttrium oxide, cerium oxide, erbium oxide, dysprosium oxide, ytterbium oxide, and combinations thereof.
根据权利要求1所述的方法，其中步骤（c）的稀土金属氧化物选自氧化钇、氧化铈、氧化铒、氧化镝、氧化镱及其组合。
12. The method of claim 1, wherein the transition metal oxides of step (c) are selected from the group consisting of hafnium oxide, titanium oxide, zirconium oxide, and combinations thereof.
如请求项1之方法，其中步骤（c）之过渡金属氧化物选自氧化铪、氧化钛、氧化锆及其组合。
13. The method of claim 1, wherein step (c) comprises infiltration with a liquid colloid.
如请求项1之方法，其中步骤（c）包含用液体胶体渗透。
14. The method of claim 13, wherein step (c) is carried out by immersing the porous core body in the liquid colloid.
根据权利要求13所述的方法，其中步骤（c）通过将多孔芯体浸入液体胶体中来执行。
15. The method of claim 13, wherein the core body treated according to step (b) comprises pores having an average, selected pore-opening size, and the particles in the liquid colloid have an average size smaller than the average pore-opening size, to permit the particles to infiltrate the pores of the core body.
根据权利要求13所述的方法，其中根据步骤（b）处理的芯体包括具有所选平均孔径的孔，并且液体胶体中的颗粒具有小于平均孔径的平均尺寸，以允许颗粒渗入芯体的孔。
16. The method of claim 15, wherein the average size of the particles in the colloid is less than about 1 micron.
如请求项15之方法，其中胶体中粒子之平均大小小于约1微米。 17. The method of claim 16, wherein the average size of the particles in the colloid is less than about 0.1 micron.
如请求项16之方法，其中胶体中粒子之平均大小小于约0.1微米。 18. The method of claim 1, wherein step (c) comprises infiltration with an aqueous or non-aqueous solution of the infiltrating particles. 根据权利要求1所述的方法，其中步骤（c）包括用渗透颗粒的水溶液或非水溶液渗透。
19. The method of claim 18, wherein the solution comprises a precursor of the material forming the particles.
如请求项18之方法，其中该溶液包含形成该粒子之材料之前驱物。 20. The method of claim 18, wherein the solution comprises at least one nitrate, nitrite, acetate, carbonate, stearate, or organometallic compound of the infiltrating particles.
如请求项18之方法，其中该溶液包含至少一种渗透粒子之硝酸盐、亚硝酸盐、乙酸盐、碳酸盐、硬脂酸盐或有机金属化合物。
21. The method of claim 1, wherein infiltration step (c) is carried out under conditions which provide at least about 0.5% by weight of the metal oxide within the core body, based on the total weight of the core body.
根据权利要求1所述的方法，其中渗透步骤（c）是在基于所述芯体的总重量在所述芯体内提供至少约0.5%（按重量计）金属氧化物的条件下进行的。
22. The method of claim 21, wherein infiltration step (c) is carried out under conditions which provide at least about 2% by weight of the metal oxide within the core body.
根据权利要求21所述的方法，其中渗透步骤（c）是在芯体内提供至少约2%（重量比）金属氧化物的条件下进行的。
23. The method of claim 1, wherein the heat treatment of step (d) is sufficient to remove the liquid component of the colloid while the particles remain in the pores, so as to maintain substantially open, surface-connected porosity in the core body.
如请求项1之方法，其中步骤（d）之热处理足以移除胶体之液体组分，而粒子仍留在孔中，以维持芯体内实质上开放且表面连接之孔隙率。
铸造难熔金属复合材料用稀土陶瓷型芯结构及相关工艺
