TYY-AA series: It has the advantages of high absorption (0.86¡«0.92/AM1.5) and low emittance(¡Ü0.08/80℃¡À5℃), which is invented by YinZhiQiang professor of Tsinhua University and used in the civil solar water heaters extensively. Its selective absorption coatings adopts the graded AL-N cermet layer. Its film structure is ALN/AL-N/AL-N/AL-N/AL-N(adhesion) which can work effectively in the 200℃