Metal Corrosion Of ACQ Wood Preservative And Its Treated Wood

Wood is easily attacked by decay fungi and insects, and preservative treatment could extend its service life and then save wood resources. ACQ (alkaline copper quat) wood preservative has been developing rapidly in recent years, and it has become the leading new generation of water-borne preservatives. During the preservative treatment of wood and the application of preservative treated wood, there are many opportunities for preservative or treated wood to be in contact with metal. Therefore, the prevention of preservative and its treated wood against metal corrosion was significant. In this study, orthogonal test was used to investigate the metal corrosion of ACQ preservative and its treated wood. Based on the results, ACQ preservative was modified, and MMT (montmorillonite) was also introduced into ACQ preservative treated wood in order to reduce the metal corrosion. The metal corrosion as well as the mechanical properties and decay resistance were all investigated for modified ACQ preservative and MMT-ACQ treated wood. This study aimed to provide references to related manufacturers and reduced the loss because of metal corrosion.The results of this study were summarized as follows:1. ACQ preservative was seriously corrosive on Q235A mild steel, red brass and hot-dipped galvanized steel, but hardly corrosive on 304 stainless steel. Therefore,304 stainless steel was applicable to situations connected with ACQ preservative or ACQ preservative treated wood. The chloride ion was the principal factor that accelerated the corrosion of Q235A mild steel. Copper oxide concentration and the mass ratio of copper oxide to monoethanolamine had remarkable influence on the corrosion of red brass in ACQ wood preservative. Copper oxide concentration, the mass ratio of copper oxide to monoethanolamine and the mass ratio of cupper oxide to DDAC all contributed to the corrosion of hot-dipped galvanized steel.2. Serious corrosion happened to Q235A mild steel and hot-dipped galvanized steel while in contact with ACQ preservative treated wood. But red brass and 304 stainless steel were hardly affected by corrosion. Copper oxide concentration was the significant factor that influenced the corrosion of Q235A steel and zinc hot galvanized steel in contact with ACQ preservative treated wood.3. ACQ preservatives formulated respectively with DDAC (didecyl dimethyl ammonium choride), DDACO3 (didecyl dimethyl ammonium carbonate) or DDACOH (didecyl dimethyl ammonium hydroxyl) showed little difference in the corrosion of red brass. The corrosion of Q235A steel and zinc hot galvanized steel was seriously influenced by modified DDAC. ACQ preservative formulated with DDACO3 was hardly corrosive to Q235A steel. And the corrosion to Q235A steel was also decreased in contact with ACQ preservative formulated with DDACOH. ACQ preservative formulated with DDACOH had less corrosion to zinc hot galvanized steel than to Q235A steel.4. ACQ preservative formulated with DDACOH and DDACO3had little influence on the leaching and decay resistance of treated wood compared with ACQ formulated with DDAC.5. Because MMT treated wood was corrosive to metal itself, MMT-ACQ treated wood exhibited more serious corrosion on metal. MMT-ACQ treated wood showed higher hardness and decay resistance, but the compression strength parallel to grain had little change.