关键词: 木材, 石蜡防水剂, 防腐, 复配, 金属腐蚀性

Abstract:

[Objective] Copper azole (CA) as a new generation of environmentally friendly water-borne wood preservative, its treated wood tends to accelerate the corrosion process of mental. To provide technical basis for reducing metal corrosion issue in wood preservation, the effects of adding paraffin wax emulsion into CA preservative on the metal corrosion of treated wood was investigated.[Method] In this work, two concentrations of CA(0.3% and 0.5%)were combined with three concentrations of paraffin wax emulsion(0.5%, 1% and 2%)to treat sapwood of Pinus spp. with the size of 19 mm(T)×38 mm(R)×89 mm(L), using a full-cell process. Weight percent gain(WPG)and retention of copper in treated wood were calculated. Furthermore, the metal corrosion of 304 stainless steel, hot dip galvanized steel and Q235A steel contacted with CA /paraffin wax emulsion compound system treated wood were tested according to the American Wood Protection Association Standard AWPA E12-08, respectively.[Result] 1) The retentions of copper in CA treated wood were (1.81±0.12)kg·m^-3 and (3.80±0.03)kg·m^-3 respectively, reaching use category C3(≥1.7 kg·m^-3) and C4A(≥3.3 kg·m^-3). 2) Q235A was the most prone to corrosion with a large area of red copper element on the surface. Hot dip galvanized steel showed mild corrosion and 304 stainless steel was almost not corroded. 3) All corrosion rate of 304 stainless steel was 0; corrosion rate of Q235A steel contacted with CA treated wood was twice or three times as much as the control, adding paraffin wax emulsion could obviously reduce the metal corrosion rate; the tendency in corrosion of hot dip galvanized steel was similar to that of Q235A steel, but its corrosion rate was much lower.[Conclusion] 1) Corrosion rate of the three metals contacted with treated wood was exhibited in the following order: Q235A steel>hot dip galvanized steel>304 stainless steel. 2) After CA treatment, wood presented much more serious corrosion for Q235A steel and hot dip galvanized steel. The corrosion rate of Q235A steel contacted with solely paraffin wax emulsion treated wood was lower than that of the control. However, there was no significant difference in the corrosion rate of hot dip galvanized steel between the two groups. 3) Adding paraffin wax emulsion to CA preservative could inhibit the corrosion of both Q235A steel and hot dip galvanized steel contacted with the preservative treated wood, and the metal corrosion rate decreased with the increasing of paraffin wax emulsion's concentration.

Key words: wood, paraffin wax emulsion, wood preservation, compound system, metal corrosion