Barium titanate Barium titanate Barium titanate is an inorganic compound with chemical formula BaTiO. Barium titanate appears white as a powder and is transparent when prepared as large crystals. It is a ferroelectric ceramic material that exhibits the photorefractive effect and piezoelectric properties. It is used in capacitors, electromechanical transducers and nonlinear optics. The solid exists in one of five polymorphs depending on temperature. From high to low temperature, these crystal symmetries of the five polymorphs are hexagonal, cubic, tetragonal, orthorhombic, and rhombohedral crystal structure. All of these phases exhibit the ferroelectric effect apart from the cubic phase. The high temperature cubic
Cutlery mustard spoon and lettuce fork. Steel was always used for more utilitarian knives, and pewter was used for some cheaper items, especially spoons. From the nineteenth century, electroplated nickel silver (EPNS) was used as a cheaper substitute for sterling silver. In 1913, the British metallurgist Harry Brearley discovered stainless steel by chance and this metal has come to be the predominant one used in cutlery. An alternative is melchior, corrosion-resistant nickel and copper alloy, which can also sometimes contain manganese and nickel-iron. Plastic cutlery is made for disposable use, and is frequently used outdoors for camping, excursions, and barbecues for