Abolishing Slavery Aided the Rise of Europe's Colonial Empires

Is it just a mere coincidence that the effective end of the slave trade in Africa coincided with the sudden acceleration of colonialism that is now termed “The Scramble for Africa”? The conventional view is that Africans were nothing but passive victims of the dastardly Europeans, lacking all agency. But is the truth more complex than this? Was the moral, political, and economic picture much more mixed? Could slavery actually have been a civilisational strength for Africa?