Abstract: A thin-film spectrally selective coating for receiver tube of vacuumed type for use in thermodynamic solar installations and operating both at medium temperature (up to 400° C.) and at high temperature (up to 550° C.), coating where the optically absorbing layer is a multilayer of cermet material of type: WyN—AlNx or MoyN—AlNx, material prepared with reactive co-sputtering technique from an Al target and a W or Mo target, process conducted under a transition regimen, under PFM (Plasma Emission Monitoring) or CVM (Cathode Voltage Monitoring) monitoring for the sole Al target, with inletting near the Al target of a N2 amount adequate for obtainment of a high-transparency, high growth rate sub-stoichiometric ceramic AlN and with inletting near the W or Mo target of a N2 amount adequate for obtainment of the sole W2N or Mo2N phase, phase very stable at high temperature, such as to make the cermet material as close as possible to the formulation W2N—AlNx or Mo2N—AlNx (with x comprised between 0.90 and 1.

Abstract: A thin-film spectrally selective coating for receiver tube of vacuumed type for use in thermodynamic solar installations and operating both at medium temperature (up to 400° C.) and at high temperature (up to 550° C.), coating where the optically absorbing layer is a multilayer of cermet material of type: WyN—AlNx or MoyN—AlNx, material prepared with reactive co-sputtering technique from an Al target and a W or Mo target, process conducted under a transition regimen, under PFM (Plasma Emission Monitoring) or CVM (Cathode Voltage Monitoring) monitoring for the sole Al target, with inletting near the Al target of a N2 amount adequate for obtainment of a high-transparency, high growth rate sub-stoichiometric ceramic AlN and with inletting near the W or Mo target of a N2 amount adequate for obtainment of the sole W2N or Mo2N phase, phase very stable at high temperature, such as to make the cermet material as close as possible to the formulation W2N—AlNx or Mo2N—AlNx (with x comprised between 0.90 and 1.

Abstract: A surface coating material for heat collector elements (HCE) of solar plants, is a multi-layer structure comprising a lower infrared-reflecting metal layer, an upper layer of a non-reflecting material, and an intermediate layer of a composite ceramic-metallic (CERMET) material having upper and lower layers of different volumetric metal fractions. The lower layer has a volumetric metal fraction higher than that of the upper CERMET layer. The ceramic matrix of the CERMET is formed by amorphous silicon dioxide (SiO2). The reflecting metal layer has a thickness ranging from 90 to 110 nm. The lower CERMET layer has a thickness ranging from 70 to 80 nm and a volumetric metal fraction in the range from 0.45 to 0.55. The upper CERMET layer has a thickness ranging from 70 to 80 nm and volumetric metal fraction ranging from 0.15 to 0.25. The layer of anti-reflecting material layer has a thickness ranging from 65 to 75 nm.