MAGNETIC TAGGING OF WOOD PRESERVATIVES

IN-SERVICE PERFORMANCE OF TREATED WOOD PRODUCTS DEPENDS ON CONSISTENTLY INTRODUCING SPECIFIED QUANTITIES (RETENTION) OF PRESERVATIVE CHEMICALS TO REQUIRED DEPTHS (PENETRATION) WITHIN THE WOOD. QUALITY CONTROL PROCEDURES TO ENSURE ADEQUATE PENETRATION AND RETENTION CURRENTLY RELY ON THE REMOVAL OF INCREMENT CORES FROM A SUBSET OF ALL TREATED MEMBERS FOR SUBSEQUENT LABORATORY ANALYSIS. THE RESEARCH EXAMINES THE FEASIBILITY OF MAGNETICALLY TAGGING WOOD PRESERVATIVES TO ENABLE SIMPLE NON-DESTRUCTIVE EVALUATION OF PENETRATION AND RETENTION OF PRESERVATIVE CHEMICALS IN TREATED WOOD. IN MAGNETIC TAGGING, A SMALL AMOUNT OF EXTREMELY FINE SENSOR PARTICLES IS UNIFORMLY DISTRIBUTED THROUGHOUT THE PRESERVATIVE PRIOR TO TREATMENT. WHEN SUBSEQUENTLY INTERROGATED BY EDDY CURRENT NONDESTRUCTIVE EVALUATION, THE TAGGED WOOD RESPONDS WITH A CHARACTERISTIC SIGNATURE THAT CAN BE RELATED TO PRESERVATIVE DISTRIBUTION. A FEATURE OF EDDY CURRENT TESTING INVOLVING MAGNETICALLY TAGGED MATERIALS IS THAT ELECTROMAGNETIC ENERGY CAN PENETRATE SIGNIFICANT THICKNESSES OF NONCONDUCTING TAGGED MATERIALS. THIS PERMITS THE VOLUMETRIC CHARACTERIZATION OF TAGGED MATERIALS. THE TECHNICAL OBJECTIVES ARE: (1) TO EVALUATE THE FEASIBILITY OF INTRODUCING FERROMAGNETIC PARTICLES INTO PRESERVATIVE CHEMICALS AND ACHIEVING PENETRATION OF THE MAGNETICALLY TAGGED PRESERVATIVE INTO WOOD, AND (2) TO EVALUATE THE FEASIBILITY OF MEASURING PENETRATION AND RETENTION OF MAGNETICALLY TAGGED PRESERVATIVE WITH EDDY CURRENT.