A lead-free piezoelectric ceramic sensor material and a preparation method thereof, and relates to the technical field of piezoelectric ceramic processing. The main raw materials of the lead-free piezoelectric ceramic sensor material disclosed in the present disclosure are a barium carbonate, a calcium carbonate, a zirconia, a titanium dioxide, a strontium carbonate, an oxidation bait, a bismuth oxide, a composite binder and a dispersant agent. The preparation method is prepared through the steps of preparing ingredients, ball milling, granulating and tableting, debinding, and sintering, and the lead-free piezoelectric ceramic sensor material can be made into a lead-free piezoelectric sensor through applying an electrode and electrode polarizing. The present disclosure has an excellent compactness and a good chemical stability. And the piezoelectric sensor made of the lead-free piezoelectric ceramic sensor material has a high sensitivity, a strong working stability, an excellent piezoelectric and has a high Curie temperature.

The present invention relates to a method for additive manufacturing of a position sensitive colored ceramic article comprising: a) providing at least one flowable ceramic component; b) forming a green body by sequential deposition of the ceramic component provided in step a) and optionally a support material not intended to be part of the final article; c) position sensitive application of a coloring substance in a solvent to at least a part of the surface of the green body formed in step b), wherein the coloring substance is applied simultaneously to the sequential deposition; d) heat treatment or curing of at least a part of the green body surface obtained in step c); wherein the method steps a)-d) are at least performed once; e) optionally removing the support material from the green body; and f) sintering the green body to obtain the ceramic article; wherein the coloring substance is a dyestuff according to ISO 18451-1:2019(E). In addition, the present invention relates to a system adapted to perform the method and a control data set configured, when implemented in an additive manufacturing system, to cause the system to execute the steps of the inventive method.

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.

A method for forming a complex shape three-dimensional ceramic article by printing a first layer of a first material having a first fraction of first ceramic particles and a first fraction of a first polymeric ceramic precursor. A second layer is printed such that it is at least partially disposed on the first layer of a second material having a second fraction of second ceramic particles and a second fraction of a second polymeric ceramic precursor. A composite of the first layer and the second layer is heated at a temperature sufficient to decompose the first and second polymeric ceramic precursors and sinter the article. During the sintering process, the first and second layers with different fractions of ceramic particles undergo different degrees of shrinkage, resulting in a tuneable mismatch of the bilayer structure and accurately achieving a targeted geometry.

Compositions comprising preceramic resins and fumed alumina are described. The compositions can also include fillers, such as silicon carbide whiskers or zirconium diboride particles. The compositions can be used as three-dimensional printable inks for preparing ceramic composites, e.g., composites having complex geometry. Inclusion of fumed alumina as a rheology modifier in the composition can provide improved printing properties for the inks compared to preceramic resin inks that do not include fumed alumina.

The invention relates to a pre-impregnated fibre-reinforced composite material in laminar form, obtained impregnating a fibrous mass with a polymeric binder composition and intended to be subjected to successive forming and pyrolysis operations to produce a fibre-reinforced composite ceramic material. The polymeric binder composition is based on one or more resins chosen from the group consisting of siloxane resins and silsesquioxane resins, and can optionally comprise one or more organic resins. The polymeric binder composition is a liquid with viscosity between 55000 and 10000 mPas at temperatures between 50° C. and 70° C. The polymeric binder composition forms a polymeric binding matrix, not cross-linked or only partially cross-linked that fills the interstices of the fibrous mass. The invention also relates to a method for making said pre-impregnated fibre-reinforced composite material in laminar form. The invention further relates to a fibre-reinforced composite ceramic material, obtained by forming and subsequent pyrolysis of a pre-impregnated fibre-reinforced composite material, as well as a method for making said material.

Disclosed is a curable composition for the manufacture, by stereolithography, of a green part made of a ceramic or metallic material, the curable composition including at least one ceramic and/or metallic powder; at least one polymerizable monomer and/or oligomer; at least one initiator for the polymerization of the polymerizable monomer(s) and/or oligomer(s). The initiator(s) are selected from iodonium, sulphonium and diazonium salts and onium salts in combination with at least one amine and/or at least one phosphine to form a charge transfer complex. The initiator(s) may generate the initiation of a thermal polymerization under the exposure to at least one source of UV, visible or IR irradiation.

A ceramic matrix composite has fibers, a ceramic matrix bonded to the fibers, and ceramic particles, distributed throughout the matrix. A method includes mixing a high char ceramic resin precursor with ceramic particles, adding a catalyst to create a mixture, heating the mixture to produce functionalized ceramic particles, and cooling the mixture to produce a resin having functionalized particles.

A method for manufacturing a sintered product from a three-dimensional object as a solution includes: a preparation step S11, a degreasing step S12, and a sintering step S13. In S11, a multilayer made of an ink containing inorganic particles and an organic material is formed to prepare a three-dimensional object. S12 includes: a first degreasing step of heating the three-dimensional object under an inert gas atmosphere at a first average degreasing temperature (T1) for a first heating time to degrease the organic material; and a second degreasing step of heating the three-dimensional object degreased in the first degreasing step, under an inert gas atmosphere at a second average degreasing temperature (T2) higher than Ti for a second heating time to degrease the organic material. In S13, the three-dimensional object degreased in the second degreasing step is sintered at an average sintering temperature higher than T2 to obtain a sintered product.

A ceramic subassembly manufactured by a 3D-printing process is described. The ceramic subassembly comprises a ceramic substrate having a sidewall extending to spaced apart first and second end surfaces. At least one via extends through the substrate from the ceramic substrate first end surface to the ceramic substrate second end surface. In cross-section, the via has a square-shape with rounded corners.