An electronic device may include conductive structures with a light-reflecting coating. The coating may have a two or four-layer thin-film interference filter. The two-layer filter may have a CrN layer and an SiCrN layer. The four-layer filter may have two CrN layers and two SiCrN layers. The two-layer filter may be used to coat relatively small conductive components. The four-layer filter may be used to coat a conductive housing sidewall. Both types of interference filter may produce a relatively uniform light blue color despite variations in coating thickness produced on account of the geometry of the underlying conductive structure.

Disclosed herein are aluminum nitride (AlN) piezoelectric materials, piezoelectric devices and related methods of fabricating said devices. The piezoelectric materials comprise a doping element that enhances the piezoelectric properties of the material and a stiffening element, which enhances the mechanical properties of the piezoelectric material. The incorporation of an enhancing and stiffening element to binary alloys of AlN, results in a quaternary AlN alloy, which reduces current trade-offs between the piezoelectric tensor component (e.sub.33), and stiffness of the material (C.sub.33).

In a general aspect, a ceramic thin film with nanotwinned regions at a tunable volume fraction is manufactured. In some aspects, a method for manufacturing a ceramic thin film on a surface of a substrate in an evacuated chamber is disclosed. The ceramic thin film includes crystalline grains; and each of the crystalline grains includes one or more nanotwinned regions. The one or more nanotwinned regions have a volume fraction in a range of 30-80% of the ceramic thin film. The ceramic thin film comprises titanium, nitrogen, and boron. A plurality of targets including a plurality of sputtering materials is prepared. A gas atmosphere in the evacuated chamber is formed. Electric power is supplied to the plurality of targets to cause co-sputtering of the plurality of sputtering materials to form the ceramic thin film with the one or more nanotwinned regions.

An exhaust valve includes a valve head and a valve stem extending from the valve head. The valve head includes a combustion face and a seat face. The combustion face and the seat face are on opposing sides of the valve head. The seat face is configured to matingly engage an opposing surface. The valve head is formed of a base material. A valve thermal management composition coats at least a portion of the seat face and comprises increased thermal conductivity relative to the base material of the valve head.

The present disclosure relates to a method of preparing a nano-porous powder material. The method includes: firstly removing A in the alloy A.sub.xT.sub.y by using an ultrasonically-assisted de-alloying method to prepare a nano-porous T coarse powder, and then, allowing the nano-porous T coarse powder to perform M-ization reaction with a gas reactant containing M to obtain a nano-porous T-M coarse powder, and finally, further crushing the nano-porous T-M coarse powder using a jet mill to obtain a nano-porous T-M fine powder. The method can achieve low-cost mass production of the nano-porous T-M fine powder, bringing broad application prospects.

A phosphor powder including phosphor particles which are a phosphor represented by a general formula M.sub.x(Si, Al).sub.2(N, O).sub.3y (where M is Li and one or more alkaline earth metal elements and 0.52x0.9 and 0.06y0.36 are satisfied) and in which a part of M is substituted with a Ce element, wherein a Si/Al atomic ratio is equal to or more than 1.5 and equal to or less than 6, an O/N atomic ratio is equal to or more than 0 and equal to or less than 0.1, 5 to 50 mol % of M is Li, and 0.5 to 10 mol % of M is Ce, and a total content of a Cr element, a Fe element, and a Ni element in the phosphor powder is equal to or less than 20.0 ppm.