US 5,738,818 A · Compression/injection molding of polymer-derived fiber reinforced ceramic matrix composite materials

Abstract

Methods of making fiber reinforced ceramic matrix composite (FRCMC) parts by compression and injection molding. The compression molding method generally includes the initial steps of placing a quantity of bulk molding compound into a female die of a mold, and pressing a male die of the mold onto the female die so as to displace the bulk molding compound throughout a cavity formed between the female and male dies, so as to form the part. The injection molding method general includes an initial step of injecting a quantity of bulk molding compound into a cavity of a mold. In both methods, the bulk molding compound is a mixture which includes pre-ceramic resin, fibers, and, if desired, filler materials. Once the part has been formed by either method, the mold is heated at a temperature and for a time associated with the pre-ceramic resin which polymerizes the resin to form a fiber-reinforced polymer composite structure. The part is then removed from the mold, and heated a second time at a temperature and for a time associated with the polymerized resin which pyrolyzes it to form the finished FRCMC structure. These methods can also be modified to allow for the molding of heterogeneous FRCMC parts wherein different portions of the part contain different types of fiber and, if desired, different filler materials, so as to vary the characteristics exhibited by each portion thereof.

Claims24

Dependent claims

A method of making a fiber reinforced ceramic matrix composite (FRCMC) part comprising the steps of:

(a) injecting a quantity of bulk molding compound comprising a pre-ceramic resin and fibers into a mold having a cavity with walls which form the exterior surfaces of the FRCMC part being molded and at least one resin outlet port connecting the mold cavity to the exterior of the mold, wherein the quantity of said fibers injected corresponds to the maximum percent by volume of fibers capable of being packed within the mold cavity, and the quantity of pre-ceramic resin injected exceeds that necessary to fill the mold cavity in conjunction with the fibers and is sufficient to cause the fibers to flow with the resin and thereafter pack together within the mold cavity, and wherein excess resin exceeding that needed in conjunction with the fibers to fill the mold cavity, flows through the packed fibers and is expelled through the at least one resin outlet port;
(b) heating the mold at a temperature and for a time associated with the pre-ceramic resin which polymerizes the resin remaining in the mold cavity to form a fiber-reinforced polymer composite structure;
(c) removing the polymerized composite structure from the mold;
and
(d) heating the polymerized composite structure at a temperature and for a time associated with the polymerized resin which pyrolizes it to form a FRCMC structure.

2 more elements

A method of making a fiber reinforced ceramic matrix composite (FRCMC) part comprising the steps of:

(a) injecting a quantity of bulk molding compound comprising a pre-ceramic resin and fibers into a mold having a cavity with walls which form the exterior surfaces of the FRCMC part being molded and at least one resin outlet port connecting the cavity of the mold to the exterior of the mold, wherein the quantity of said fibers injected corresponds to the maximum percent by volume of fibers capable of being packed within a first portion of the the mold cavity and the quantity of pre-ceramic resin injected exceeds that necessary to fill the mold cavity in conjunction with the fibers and is sufficient to cause the fibers to flow with the resin and thereafter pack together within the first portion of the mold cavity, and wherein excess resin exceeding that needed in conjunction with the fibers to fill the mold cavity, flows through the packed fibers and is expelled through the at least one resin outlet port;
(b) sequentially injecting at least one additional quantity of bulk molding compound into the mold, wherein each additional quantity of bulk molding compound comprises an additional amount of the pre-ceramic resin and an additional amount of fibers, wherein the quantity of each additional amount of fibers injected corresponds to the maximum percent by volume of fibers capable of being packed within a respective additional portion of the mold cavity located adjacent a previous filled portion of the mold cavity, and wherein the quantity of each additional amount of pre-ceramic resin injected exceeds that necessary to fill the mold cavity in conjunction with the fibers and is sufficient to cause the associated additional amount of fibers to flow with the resin and thereafter pack together within the corresponding additional portion of the mold cavity, and wherein excess resin exceeding that needed in conjunction with all the fibers to fill the mold cavity, flows through the packed fibers and is expelled through the at least one resin outlet port;
(b) heating the mold at a temperature and for a time associated with the pre-ceramic resin which polymerizes the resin remaining in the mold cavity to form a fiber-reinforced polymer composite structure;
(c) removing the polymerized composite structure from the mold;
and
(d) heating the polymerized composite structure at a temperature and for a time associated with the polymerized resin which pyrolizes it to form a FRCMC structure.

3 more elements

Dependencies are inferred from the claim text.

Compression/injection molding of polymer-derived fiber reinforced ceramic matrix composite materials

Life of this patent

Compression/injection molding of polymer-derived fiber reinforced ceramic matrix composite materials

Life of this patent

Abstract

Claims24