Crystals having a modified regular tetrahedron shape are provided. Crystals preferably have four substantially identical triangular faces that define four truncated vertices and six chamfered edges. The six chamfered edges can have an average length of l, and an average width of w, and 8?l/w?9.5.

The present invention relates to a process for preparing epitaxial -quartz layers on a solid substrate, to the material obtained according to this process, and to the various uses thereof, especially in the electronics field.

The present invention relates to a process for preparing epitaxial -quartz layers on a solid substrate, to the material obtained according to this process, and to the various uses thereof, especially in the electronics field.

The purpose of quartz homeotypes grown epitaxially on beta quartz for use in pressure sensors or accelerometers is to be able to drastically cut down production costs on otherwise expensive or time-consuming to grow crystals that are necessary in various industrial applications. This is done via epitaxial growth of quartz homeotypes across the whole surface of a sample of beta quartz, an easily accessible and high temperature capable crystal. This invention also applies to the epitaxial application of piezoelectric material atop a piezoelectric crystal for the purpose of altering its piezoelectric coefficient and the epitaxial application of a piezoelectric crystal atop a host crystal for the purpose of increasing its insulation resistance.

The purpose of quartz homeotypes grown epitaxially on beta quartz for use in pressure sensors or accelerometers is to be able to drastically cut down production costs on otherwise expensive or time-consuming to grow crystals that are necessary in various industrial applications. This is done via epitaxial growth of quartz homeotypes across the whole surface of a sample of beta quartz, an easily accessible and high temperature capable crystal. This invention also applies to the epitaxial application of piezoelectric material atop a piezoelectric crystal for the purpose of altering its piezoelectric coefficient and the epitaxial application of a piezoelectric crystal atop a host crystal for the purpose of increasing its insulation resistance.

A method of forming single and few layer graphene on a quartz substrate in one embodiment includes providing a quartz substrate, melting a portion of the quartz substrate, diffusing a form of carbon into the melted portion to form a carbon and quartz mixture, and precipitating at least one graphene layer out of the carbon and quartz mixture.

An artificial quartz crystal growth method that includes applying a pressure that causes at least two substantially rectangular-parallelepiped-shaped quartz crystal substrates to abut each other in an X-axis direction with crystallographic axis directions of the quartz crystal substrates aligned with each other, and causing the at least two quartz crystal substrates to grow an artificial quartz crystal in a state where the pressure is being applied.

An artificial quartz crystal growth method that includes applying a pressure that causes at least two substantially rectangular-parallelepiped-shaped quartz crystal substrates to abut each other in an X-axis direction with crystallographic axis directions of the quartz crystal substrates aligned with each other, and causing the at least two quartz crystal substrates to grow an artificial quartz crystal in a state where the pressure is being applied.

A method for producing a component includes joining individual wall parts, especially for producing a melting crucible for use at a high operating temperature in a crucible-pulling method for quartz glass, wherein at least two wall parts of a refractory metal or of a base alloy of a refractory metal are provided, butt-joined to form a joint and joined together by sintering at a temperature above 1500 C. to form the component. A sealant is inserted into the joint to provide a component of improved tightness and to ensure improved sintering of the individual parts of the component. A component produced according to the method, particularly a melting crucible, particularly in a crucible pulling method for quartz glass, has the joint between the butt-joined walls closed in a gas-tight manner by a sealant.

A method for producing a component includes joining individual wall parts, especially for producing a melting crucible for use at a high operating temperature in a crucible-pulling method for quartz glass, wherein at least two wall parts of a refractory metal or of a base alloy of a refractory metal are provided, butt-joined to form a joint and joined together by sintering at a temperature above 1500 C. to form the component. A sealant is inserted into the joint to provide a component of improved tightness and to ensure improved sintering of the individual parts of the component. A component produced according to the method, particularly a melting crucible, particularly in a crucible pulling method for quartz glass, has the joint between the butt-joined walls closed in a gas-tight manner by a sealant.