Preform for making a component of a braking system
AssigneeFreni Brembo S.p.A.
InventorsLorenzo Cavalli, Luca Menapace
Life of this patent
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Abstract
A preform for making a component of a braking system having a fibre-reinforced ceramic composite material, obtained by forming and subsequent pyrolysis of a pre-preg is described. Also described is a component of a braking system made wholly or in part from the preform, and a method for making a preform in a fibre-reinforced ceramic composite material.
Claims24
A preform for making a component of a braking system, consisting of a fibre-reinforced ceramic composite material, obtained by forming and subsequent pyrolysis of a pre-preg, wherein said pre-preg consists of a fibrous mass impregnated with a polymeric binder composition based on one or more resins selected from the group consisting of siloxane resins and silsesquioxane resins and may optionally comprise one or more organic resins, said siloxane resins comprising polysiloxanes and said silsesquioxane resins comprising polysilsesquioxanes, wherein said polymeric binder composition appears as a liquid having viscosity of between 55000 and 10000 mPAs at temperatures of between 50° C. and 70° C., wherein said fibre-reinforced ceramic composite material comprises a ceramic or partially ceramic matrix, which develops itself in the interstices of the fibrous mass and comprises silicon carbide and amorphous structures consisting of Si—O—C chains, said silicon carbide and said Si—O—C chains having been generated by a pyrolysis process on said polysiloxanes and/or said polysilsesquioxanes, said fibre-reinforced ceramic composite material having a porosity generated by the pyrolysis on the polymeric binder composition of the pre-preg,
- wherein said polymeric binder composition further comprises at least one solvent, selected from the compounds able to solubilize siloxane resins and silsesquioxane resins, said solvent being divinylbenzene, said solvent constituting less than 1% by weight of said pre-preg,
- said braking system component being obtained by subjecting said preform to densification processes, using the Polymer Infiltration Pyrolysis (PIP) technique, said component being a component of a disc brake, including a braking band, a bell or a brake caliper body.
A method for making a preform of a fibre-reinforced composite ceramic material, comprising the following operating steps:
- arranging a pre-preg impregnated with a polymeric binder composition;
- and
- forming said pre-preg bringing said polymeric binder composition to at least a partial curing, obtaining a fibre-reinforced composite material;
- subjecting said fibre-reinforced composite material to pyrolysis at a temperature of between 400° C. and 1,500° C., so as to obtain said preform
- wherein said pre-preg comprises a fibrous mass impregnated with a polymeric binder composition based on one or more resins selected from the group consisting of siloxane resins and silsesquioxane resins and may optionally comprise one or more organic resins, said siloxane resins comprising polysiloxanes and said silsesquioxane resins comprising polysilsesquioxanes, wherein said polymeric binder composition appears as a liquid, having a viscosity of between 55000 and 10000 mPas at a temperature of between 50° C. and 70° C.,
- wherein said forming leads to the curing of said one or more resins of the polymeric binder composition, and thus to the formation of a solid polymeric binder matrix, which develops itself in the interstices of the fibrous mass and is based on polysiloxanes and/or polysilsesquioxanes, cross-linked with each other as a result of the cross-linking induced by the curing of said one or more resins of the polymeric binder composition, and wherein said pyrolysis causes the formation of porosity in said solid polymeric binder matrix due to a partial degradation of the solid polymeric binder matrix and the at least partial transformation of said polysiloxanes and/or polysilsesquioxanes into silicon carbide and amorphous structures consisting of Si—O—C chains, so as to obtain a fibre-reinforced ceramic composite material from said fibre-reinforced composite material.
Dependencies are inferred from the claim text.