Patent ID: 7686990

Claim:
A method of producing a ceramic matrix composite article having an exterior surface with a net shape, the method comprising the steps of: providing a body comprising a fiber reinforcement material, a matrix material surrounding the fiber reinforcement material, an external surface defined by the matrix material, and internal porosity within the body and open to the external surface; depositing on the external surface of the body a coating comprising a carbonaceous binder and a slurry containing a ceramic particulate material, the coating covering the external surface of the body and defining an external coating surface on the body at which the fiber reinforcement material is not exposed; curing the carbonaceous binder to render the coating machinable; machining the coating to remove only surface portions of the coating and yield an external machined coating surface that approximately produces the net shape of the article, the coating being sufficiently thick such that machining of the coating does not expose the fiber reinforcement material within the body; melt infiltrating the body with a melt infiltration material while the coating contacts and conforms to a die surface; and then reacting the melt infiltration material to form a ceramic matrix within a composite substrate containing the fiber reinforcement material, the coating forms a ceramic coating bonded to the composite substrate to form the article, and the ceramic coating defines the external surface substantially having the net shape.