RT2Al10 is a new series of rare-earth-based ternary aluminide compounds that show a variety of magnetic phenomena. This proposal is for a muSR study on three of its members to investigate magnetic ordering in CeRu2Al10, and electronic correlation phenomena in YFe2Al10, and YbFe2Al10. In an October 2009 experiment at ILL we have found three very weak magnetic Bragg peaks in CeRu2Al10, which are ascribed to the anomalously high magnetic ordering temperature of TN=27 K. We wish to determine the magnetic order parameter using muSR, since neutron diffraction on the very weak intensity peaks is extremely difficult. The Fe-containing compounds, on the other hand, show effects of electronic correlation with putative quantum criticality at low temperatures, and for these we propose to trace the muon relaxation spectra as a function of temperature to probe the nature of the correlations.