Fretting Wear Behavior of Cr Coated Zr-1Nb Alloy Cladding in High Temperature and High Pressure Water

The fretting wear behaviors of Cr-coated Zr-1Nb cladding tube with different griding pairs in simulated pressurized water reactor primary water environment at 290 and 310 degrees C were studied by three-dimensional optical surface profilometer, scanning electron microscope, electron backscattered diffraction and energy spectrometer. The results show that the fretting wear behaviors between the Cr-coated Zr-1Nb cladding and griding pairs (i.e., Zr-4 dimple or Inconel 718 spring) are both dominated by the adhesive wear mechanism, accompanied by material transfer from the grinding pair to the Cr-coated cladding. With the increase in temperature, the fretting wear resistance of the Cr-coated cladding is decreased, as manifested by increased surface wear depth and volume. However, the fretting wear mechanism still remains unchanged within the temperature range tested in this work. In addition, the wear degree of the Cr-coated cladding with Zr-4 dimple is greater than that with Inconel 718 spring, which is related to the hardness and contact mode of the grinding pair.