Geopolymer cements (GPs)possess the ability to form high-strength,thermally-stable,and near-net shape structures at room temperature.It has been found that GPs can also be used tobond both metals and ceramics.Unlike organics,geopolymers can be heated to elevatedtemperatures and are easier to apply as compared to refractory adhesives.Many refractoryadhesives require at least one,if not multiple curing steps,at elevated temperatures before theycan be used in service.Geopolymers,however,need only be cured once at relatively lowtemperatures (40 -80 °C)to complete their curing process.Geopolymers contain no organiccarriers often found in refractory adhesives,and can be processed from inexpensive andrelatively non-toxic materials,I.e.waterglass and calcined aluminosilicate clays.This studydetails how geopolymer cements can be used to bond 6061-T6 aluminum alloy,1008/1010 steel,alumina,and borosilicate glass at both ambient and elevated temperatures (25 -450 °C).Shearstrength values of various samples were determined according to ASTM D1002-01 (single)andASTM D3528-96 (double)shear lap tests.The microstructure and chemical composition of thegeopolymer bond as well as interface were studied with scanning electron microscopy (SEM)and energy dispersive spectroscopy (EDS)in the SEM.
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