How were african american slaves treated while serving in the union military?

I think it might be this Crispus Attucks was an iconic patriot; engaging in a protest in 1770, he was shot by royal soldiers in the Boston Massacre

African-Americans as slaves and free blacks served on both sides during the war. Gary Nash reports that recent research concludes there were about 9000 black Patriot soldiers, counting the Continental Army and Navy, and state militia units, as well as privateers, wagoneers in the Army, servants to officers, and spies.[1] Ray Raphael notes that while thousands did join the Loyalist cause, "A far larger number, free as well as slave, tried to further their interests by siding with the patriots."[2]

Black soldiers served in Northern militias from the outset, but this was forbidden in the South, where slave-owners feared arming slaves. Lord Dunmore, the Royal Governor of Virginia, issued an emancipation proclamation in November 1775, promising freedom to runaway slaves who fought for the British; Sir Henry Clinton issued a similar edict in New York in 1779.[3] Over 100,000 slaves escaped to the British lines, although possibly as few as 1,000 served under arms. Many of the rest served as orderlies, mechanics, laborers, servants, scouts and guides, although more than half died in smallpox epidemics that swept the British forces, and many were driven out of the British lines when food ran low. Despite Dunmore's promises, the majority were not given their freedom. [citation needed] Many Black Loyalists' descendants now live in Canada and Sierra Leone. Many of the Black Loyalists performed military service in the British Army, particularly as part of the only Black regiment of the war, the Black Pioneers, and others served non-military roles. Good luck but you ight want to wait for another answer.

It's hard to compete with maysa's answer but slaves back then were never treated well, even if they were in the union fighting against the south ... Lots of people blamed the war on the Africans which made the white folk hate them even more. Also I heard Africans were screamed at or beaten even while they were marching towards then enemy ...