Sanhua will introduce trivalent chromium pretreatment (TCP) coating technology at 2017 AHR Expo. Sanhua has already developed a mature process involving the application of TCP coating on microchannel heat exchangers (MCHEs), in the U.S. and Asian markets. It is believed that this solution will provide added value for Sanhua and its strategic partners.
MCHE coils are designed to use less refrigerant and facilitate better heat transfer. These coils are constructed with all-aluminum alloys, and unprotected MCHE coils will face corrosion issues in corrosive atmospheres. TCP technology has been developed for aluminum and aluminum alloys. The TCP coating provides a chemical conversion layer to protect the MCHE coils against corrosive atmospheres. The thickness of the TCP coating is nano-scale, and thus the thin coating does not affect heat transfer or air flow. According to lab tests, the TCP coating can at least double the lifetime as demonstrated by the Acidified Synthetic Sea Water Testing (SWAAT Test) compared with bare MCHE coils. It can help to extend the application of MCHEs in the corrosive field with reasonable cost, filling the gap that electrophoretic coating (e-coating) cannot cover due to high cost.