In the Hero of Ages and in a few other Mistborn books, we see that hemalurgic creations, namely Marsh, were able to maintain a sliver of their own autonomy, even while being controlled by Ruin or another Shard/allomancer. Electrum is capable of storing determination, and compounding it would magnify that determination. So, if you were burning an electrum metalmind and Harmony tried to take over your mind, would you be able to resist him through virtue of nothing but pure willpower?