Some effects of CO sub 2, Co and H sub 2 O upon the properties of Ba sub 2 YCu sub 3 O sub 7.

Thermogravimetric (TG) curves are presented for heating Ba sub 2 YCu sub 3 O sub 7 up to 1000C in CO sub 2, CO, several mixtures of CO sub 2 in O sub 2, and in wet O sub 2 and wet CO sub 2. In pure CO sub 2 there is a small weight loss up to about 400C, presumably due to O sub 2 evolution caused by the low P sub (O2). This decrease in weight is followed by a large weight gain up to about 90C at which point the carbonate formed just begins to decompose. The behavior in Co is similar except the loss of O sub 2 is much greater. In wet O sub 2 there is a very slight weight gain beginning around 300C followed by the normal loss of weight associated with O sub 2 evolution and decomposition of any hydroxide formed earlier.