In 19.1, we cannot put the y2 axis on the right side of the chart. It only shows up on the left side.
using Aspose.Slides;
using Aspose.Slides.Charts;
using Aspose.Slides.Export;
string dataDir = @"C:\AsposeTest\";
using (Presentation pres = new Presentation())
{
IChart chart = pres.Slides[0].Shapes.AddChart(ChartType.ClusteredColumn, 100, 100, 400, 300);
//Switching rows and columns
chart.ChartData.SwitchRowColumn();
//Plotting on second axis
chart.ChartData.Series[0].PlotOnSecondAxis = true;
pres.Save(dataDir + "Test.pptx", SaveFormat.Pptx);
}